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Sample records for abyssal hill faults

  1. Milankovich Sea Level-Change Pumping of Fault Slip May Enhance Abyssal Hill Growth, with Spacing Control by Melt Pumping or Elastic Properties

    NASA Astrophysics Data System (ADS)

    Macdonald, K. C.

    2015-12-01

    Sea level-change pumping of mantle melt to create abyssal hills is a very innovative and elegant hypothesis. However, I see 2 issues: 1. Abyssal hill observations indicate that they are bounded by normal faults in most cases. 2. The resolution of the crustal accretion "tape recorder" and its ability to accurately record cycles as short as 20Kyr and 40Kyr is limited given the width of the zone of crustal accretion. Magnetic anomaly polarity transition widths give us one measure of estimating the resolution of this tape recorder. Based on these measurements, the half-width of the zone of crustal accretion ranges from 1-8 km, with 2-4 km being typical. At a half-spreading rate of 3 cm/yr, a width of 3km of crust is created during the 100Kyr Milankovich cycle, ~1.2 km during the 40Kyr cycle, and 600m during the 20Kyr cycle, so only the 100K signal is likely to be resolvable. In contrast, consider the effect of pressure changes on fault slip. In critically stressed lithosphere, a small change in pressure can produce nearly instantaneous slip. For example, pressure changes of only ~0.1 MPa near injection wells in OK, TX trigger earthquakes at depths of 3-5 km (Mark Zoback, personal comm.). This pressure change is equivalent to a 100 m sea level change. For the 20Kyr and 40Kyr cycles, sea level-change pumping of fault slip may dominate because fault uplift of abyssal hills is not smeared by the time-averaging effects of crustal accretion. The spacing of the abyssal hills in this scenario would be controlled by the elastic thickness and flexural rigidity of young lithosphere. Faulting also can accommodate variations in melt supply, with most of the melt freezing at depth; this would explain why we observe dominantly tectonic rather than constructional volcanic origins of abyssal hills. If abyssal hills are caused by variations in melt production, the crust should be measurably thicker beneath the axes of the hills. If faulting dominates, crustal thickness would be more

  2. Abyssal Hill Segmentation: Quantitative analysis of the East Pacific Rise flanks 7°S-9°S

    NASA Astrophysics Data System (ADS)

    Goff, John A.; Malinverno, Alberto; Fornari, Daniel J.; Cochran, James R.

    1993-08-01

    The recent R/V Maurice Ewing EW9105 Hydrosweep survey of the East Pacific Rise (EPR) and adjacent flanks between 7°S and 9°S provides an excellent opportunity to explore the causal relationship between the ridge and the abyssal hills which form on its flanks. These data cover 100% of the flanking abyssal hills to 115 km on either side of the axis. We apply the methodology of Goff and Jordan (1988) for estimating statistical characteristics of abyssal hill morphology (rms height, characteristic lengths and widths, plan view aspect ratio, azimuthal orientation, and fractal dimension). Principal observations include the following: (1) the rms height of abyssal hill morphology is negatively correlated with the width of the 5- to 20-km-wide crestal high, consistent with the observations of Goff (1991) for northern EPR abyssal hill morphology; (2) the characteristic abyssal hill width displays no systematic variation with position relative to ridge segmentation within the EW9105 survey area, in contrast with observations of Goff (1991) for northern EPR abyssal hill morphology in which characteristic widths tend to be smallest at segment ends and largest toward the middle of segments; (3) abyssal hill rms heights and characteristic widths are very large just north of a counterclockwise rotating "nannoplate", suggesting that the overlap region is being pushed northward in response to microplate-style tectonics; and (4) within the 7°12'S-8°38'S segment, abyssal hill lineaments are generally parallel to the ridge axis, while south of this area, abyssal hill lineaments rotate with a larger "radius of curvature" than does the EPR axis approaching the EPR-Wilkes ridge-transform intersection.

  3. Evidence for Pulsed Hydrothermal Venting from Young Abyssal Hills on the EPR Flank Suggests Frequent Seismic Pumping of Ridge Flank Fluid Flow

    NASA Astrophysics Data System (ADS)

    Haymon, R. M.; MacDonald, K. C.; Benjamin, S. B.; Ehrhardt, C. J.

    2004-12-01

    Although measured heat flow suggests that 40-50% of oceanic hydrothermal heat and fluid flux is from young (0.1-5 Ma) abyssal hill terrain on MOR flanks, hydrothermal vents in this setting rarely have been found. On the EPR flanks, seafloor evidence of venting from abyssal hills has been discovered recently at two sites: on ˜0.1 Ma seafloor at 10° 20'N, 103° 33.2'W ("Tevnia Site") and on ˜0.5 Ma seafloor at 9° 27'N, 104° 32.3'W ("Macrobes Site"). Manifestations of venting at these sites include: fault scarp hydrothermal mineralization and macrofauna; fault scarp flocculations containing hyperthermophilic microbes; and hilltop sediment mounds and craters possibly created by fluid "blow-outs." Hydrothermal deposits recovered at the ˜0.1 Ma "Tevnia Site" are fault breccias that record many episodes of brecciation followed by hydrothermal cementation (Benjamin et al., this session). Tubeworm casings, live crabs, and "dandelions" observed at this site indicate that the most recent episode of venting was active during, or shortly before, this site was visited with Alvin in 1994. To create the 200 m-high axis-facing fault scarp at Tevnia Site in 100,000 years, an average uplift rate of at least 2 cm/y is required. Since off-axis earthquakes located on abyssal hill fault scarps typically are fault slippage must repeat on a decadal timescale to match the observed rate of hill uplift, probably breaking open the fault scarp and rejuvenating hydrothermal flow on a very frequent basis. In addition, close proximity to Clipperton Transform may subject Tevnia Site to frequent M5-M6 seismic events with strong ground shaking and hydraulic pressure pulses capable of breaking open subseafloor pathways clogged with fragile minerals. We hypothesize that the multiple brecciation/cementation events recorded in the Tevnia Site samples, and biological evidence for recent venting at the

  4. Petrological, magnetic and chemical properties of basalt dredged from an abyssal hill in the North-east pacific

    USGS Publications Warehouse

    Luyendyk, B.P.; Engel, C.G.

    1969-01-01

    OVER the years, samples of basalt from the oceanic crust have been taken mainly from seamounts, fracture zones and ridge and rise crests1-6, and rarely from the vast fields of abyssal hills which cover a large part of the deep-sea floor. The basalt sampled from the deeper regions of the oceanic crust (for example, on fault scarps) is a distinct variety of tholeiitic basalt, while alkali basalt is restricted to the volcanic edifices4. Oceanic tholeiitic basalt differs from alkali basalt and continental tholeiite chiefly in having a relatively low percentage of K2O (0.2 weight per cent)4. Some authors have speculated that this type of tholeiitic basalt is the major extrusion from the upper mantle and constitutes the predominant rock type in the upper oceanic crust. ?? 1969 Nature Publishing Group.

  5. Hydrothermal Mineral Deposits From a Young (0.1Ma) Abyssal Hill on the Flank of the Fast-Spreading East Pacific Rise

    NASA Astrophysics Data System (ADS)

    Benjamin, S. B.; Haymon, R. M.

    2004-12-01

    It has been estimated from heat flow measurements that at least 40% of the total hydrothermal heat lost from oceanic lithosphere is removed from 0.1-5 Ma abyssal hill terrain on mid-ocean ridge flanks. Despite the large magnitude of estimated hydrothermal heat loss from young abyssal hills, little is known about characteristics of hydrothermal vents and mineral deposits in this setting. This study describes the first abyssal hill hydrothermal samples to be collected on the flank of a fast-spreading ridge. The mineral deposits were discovered at "Tevnia Site" on the axis-facing fault scarp of an abyssal hill, located on ˜0.1 Ma lithosphere ˜5 km east of the East Pacific Rise (EPR) axis at 10\\deg 20'N. Observations of Galatheid crabs, "dandelion" siphonophores, and colonies of dead, yet still intact, Tevnia worm tubes at this site during Alvin dives in 1994 suggests relatively recent hydrothermal activity. The deposits are friable hydrothermal precipitates incorporating volcanic clasts brecciated at both the micro and macro scales. The petrographic sequence of brecciation, alteration, and cementation exhibited by the samples suggests that they formed from many pulses of hydrothermal venting interspersed with, and perhaps triggered by, repeated tectonic events as the abyssal hill was uplifted and moved off-axis (see also Haymon et al., this session). Observed minerals include x-ray amorphous opaline silica and Fe-oxide phases, crystalline Mn-oxides (birnessite and todorokite), an irregularly stratified mixed layer nontronite-celadonite, and residual calcite in sediment-derived microfossils incorporated into the breccia matrix. This mineral assemblage suggests that the deposits precipitated from moderately low-temperature (<140\\deg C) fluids, enriched in K, Fe, Si, and Mn, with a near-neutral pH. The presence of tubeworm casings at the site is evidence that the hydrothermal fluids carried H2S, however no metal sulfide phases were identified in the samples. Although

  6. Abyssal hills - hidden source of increased habitat heterogeneity, benthic megafaunal biomass and diversity in the deep sea

    NASA Astrophysics Data System (ADS)

    Durden, Jennifer M.; Bett, Brian J.; Jones, Daniel O. B.; Huvenne, Veerle A. I.; Ruhl, Henry A.

    2015-09-01

    Abyssal hills are the most abundant landform on Earth, yet the ecological impact of the resulting habitat heterogeneity on the wider abyss is largely unexplored. Topographic features are known to influence food availability and the sedimentary environment in other deep-sea habitats, in turn affecting the species assemblage and biomass. To assess this spatial variation, benthic assemblages and environmental conditions were compared at four hill and four plain sites at the Porcupine Abyssal Plain. Here we show that differences in megabenthic communities on abyssal hills and the adjacent plain are related to environmental conditions, which may be caused by local topography and hydrodynamics. Although these hills may receive similar particulate organic carbon flux (food supply from the surface ocean) to the adjacent plain, they differ significantly in depth, slope, and sediment particle size distribution. We found that megafaunal biomass was significantly greater on the hills (mean 13.45 g m-2, 95% confidence interval 9.25-19.36 g m-2) than the plain (4.34 g m-2, 95% CI 2.08-8.27 g m-2; ANOVA F(1, 6) = 23.8, p < 0.01). Assemblage and trophic compositions by both density and biomass measures were significantly different between the hill and plain, and correlated with sediment particle size distributions. Hydrodynamic conditions responsible for the local sedimentary environment may be the mechanism driving these assemblage differences. Since the ecological heterogeneity provided by hills in the abyss has been underappreciated, regional assessments of abyssal biological heterogeneity and diversity may be considerably higher than previously thought.

  7. Evolution of the Puente Hills Thrust Fault

    NASA Astrophysics Data System (ADS)

    Bergen, K. J.; Shaw, J. H.; Dolan, J. F.

    2013-12-01

    This study aims to assess the evolution of the blind Puente Hills thrust fault system (PHT) by determining its age of initiation, lateral propagation history, and changes in slip rate over time. The PHT presents one of the largest seismic hazards in the United States, given its location beneath downtown Los Angeles. The PHT is comprised of three fault segments: the Los Angeles (LA), Santa Fe Springs (SFS), and Coyote Hills (CH). The LA and SFS segments are characterized by growth stratigraphy where folds formed by uplift on the fault segments have been continually buried by sediment from the Los Angeles and San Gabriel rivers. The CH segment has developed topography and is characterized by onlapping growth stratigraphy. This depositional setting gives us the unique opportunity to measure uplift on the LA and SFS fault segments, and minimum uplift on the CH fault segment, as the difference in sediment thicknesses across the buried folds. We utilize depth converted oil industry seismic reflection data to image the fold geometries. Identifying time-correlative stratigraphic markers for slip rate determination in the basin has been a problem for researchers in the past, however, as the faunal assemblages observed in wells are time-transgressive by nature. To overcome this, we utilize the sequence stratigraphic model and well picks of Ponti et al. (2007) as a basis for mapping time-correlative sequence boundaries throughout our industry seismic reflection data from the present to the Pleistocene. From the Pleistocene to Miocene we identify additional sequence boundaries in our seismic reflection data from imaged sequence geometries and by correlating industry well formation tops. The sequence and formation top picks are then used to build 3-dimensional surfaces in the modeling program Gocad. From these surfaces we measure the change in thicknesses across the folds to obtain uplift rates between each sequence boundary. Our results show three distinct phases of

  8. Seismic Interpretation and Quantification of Abyssal-Hill-Scale Pelagic Sedimentation Regimes in the 0-53 Ma Eastern Equatorial Pacific

    NASA Astrophysics Data System (ADS)

    Tominaga, M.; Lyle, M. W.; Mitchell, N.

    2009-12-01

    To evaluate paleoceanographic conditions from chemical and physical records in pelagic sediments more accurately, it is imperative to understand how the sediment has been transported, deposited and eroded. To date, few researchers have studied how these processes have affected seafloor topography over time, and the works were limited to near surface data or to narrow geographic regions (e.g., Laguros and Shipley, 1989; Jordan and Webb, 1996; Malinverno, 1995; Mitchell, 1996). In this study, we have investigated pelagic sedimentation regimes across various parts of the 0-53 Ma eastern-central equatorial Pacific where changes in sedimentation rates are significant. Our goals are to quantify (1) abyssal-hill-scale primary deposition regimes with respect to the equatorial high productivity zone, and (2) the extent to which seafloor topography has been subdued by abyssal valley-filling. We used a recently collected seismic reflection data set (AMAT03 on R/V Revelle, 2006) aided by information from Deep Sea Drilling Project (DSDP) and Ocean Drilling Program (ODP) holes where the seismic survey lines cross ODP Site 849, DSDP 572, and 80, and Integrated Ocean Drilling Program Site U1331-1338. The seismic data were collected using 4 and 48 channel streamers for underway and around-site surveys, respectively, and were processed by band-pass filtering, normal move-out, stacking, and F-K migration. The seafloor in this region is characterized by a series of abyssal hills and basins, with minor late stage faulting in the basement and some seamounts identifiable in multibeam sonar data also collected on the cruise. We focused on three long profiles that transect a series of abyssal hills and basins, and 10 and 8 selected study sites from underway and site-survey profiles, respectively. We revisited the seismic stratigraphy of Mayer et al. (1985, 1986) and Bloomer et al. (1995) to estimate ages of our interpreted seismic horizons. Overall, we recognized three different

  9. Hydrothermal mineral deposits and fossil biota from a young (0.1 Ma) abyssal hill on the flank of the fast spreading East Pacific Rise: Evidence for pulsed hydrothermal flow and tectonic tapping of axial heat and fluids

    NASA Astrophysics Data System (ADS)

    Benjamin, Sara B.; Haymon, Rachel M.

    2006-05-01

    Heat flow data indicate that most hydrothermal heat loss from ocean lithosphere occurs on the flanks of the mid-ocean ridge, but few ridge flank hydrothermal sites are known. We describe the first nonseamount, abyssal hill hydrothermal mineral deposits to be recovered from the fast spreading East Pacific Rise (EPR) flanks. Deposits were sampled at two sites on an abyssal hill ˜5 km east of the EPR axis, just north of Clipperton Fracture Zone at 10°20'N, on ˜0.1 Ma lithosphere. "Tevnia Site" is on the axis-facing fault scarp of the hill, and "Ochre Site" is located ˜950 m farther east near the base of the outward-facing slope. Clusters of fragile, biodegradable Tevnia worm tubes at both sites indicate that hydrothermal fluids carried sufficient H2S to sustain Tevnia worms, and that fluid flow waned too recently to allow time for tube destruction. Presence of microbial mats and other biota also are consistent with recent waning of flow. The deposits are mineralogically zoned, from nontronite-celadonite to hydrous Fe-oxide+opaline silica to Mn-oxide (birnessite and todorokite). This places them into a distinctive class of Fe-Si-Mn hydrothermal deposits found along tectonic cracks and faults in young oceanic crust, and suggests that (1) deposits precipitated along an O2 gradient between ambient seawater and hydrothermal fluid; (2) fluid temperatures were <150°C and (3) undiluted fluids were Mg-depleted, and Fe-, K-, Si- and Mn-enriched. These fluids may derive from high temperature seawater-basalt interaction ± phase separation proximal to the axial melt zone, and lose Cu and Zn before venting due to conductive cooling and/or pH increase. Ochre Site samples are purely hydrothermal; however, Tevnia Site samples incorporate volcanic, sedimentary, and fossil components, and exhibit at least three generations of fracturing and hydrothermal cementation. The Tevnia Site breccias accumulated on the exposed fault scarp, possibly during multiple slip events and

  10. Surface faulting along the Superstition Hills fault zone and nearby faults associated with the earthquakes of 24 November 1987

    USGS Publications Warehouse

    Sharp, R.V.

    1989-01-01

    The M6.2 Elmore Desert Ranch earthquake of 24 November 1987 was associated spatially and probably temporally with left-lateral surface rupture on many northeast-trending faults in and near the Superstition Hills in western Imperial Valley. Three curving discontinuous principal zones of rupture among these breaks extended northeastward from near the Superstition Hills fault zone as far as 9km; the maximum observed surface slip, 12.5cm, was on the northern of the three, the Elmore Ranch fault, at a point near the epicenter. Twelve hours after the Elmore Ranch earthquake, the M6.6 Superstition Hills earthquake occurred near the northwest end of the right-lateral Superstition Hills fault zone. We measured displacements over 339 days at as many as 296 sites along the Superstition Hills fault zone, and repeated measurements at 49 sites provided sufficient data to fit with a simple power law. The overall distributions of right-lateral displacement at 1 day and the estimated final slip are nearly symmetrical about the midpoint of the surface rupture. The average estimated final right-lateral slip for the Superstition Hills fault zone is ~54cm. The average left-lateral slip for the conjugate faults trending northeastward is ~23cm. The southernmost ruptured member of the Superstition Hills fault zone, newly named the Wienert fault, extends the known length of the zone by about 4km. -from Authors

  11. Possible Late Quaternary faulting in the Benton Hills, southeastern Missouri

    SciTech Connect

    Palmer, J.R.; Hoffman, D. . Dept. of Natural Resources)

    1993-03-01

    Geologic mapping in the 1930's by Dan Stewart and Lyle McManamy identified numerous faults in the Thebes Gap area of the Benton Hills, including two post-late Quaternary faults (max. of 10 m displacement) along the southeastern escarpment. Recent geologic mapping (Richard Harrison, pers. comm.) suggests dextral strike-slip displacement on most of these faults; some deformation post-dates the Pliocene-Pleistocene Mounds gravel. Small historical earthquake epicenters have been recorded in the Benton Hills area. Review of these data and analysis of the geologic and structural relationships to small- and large-scale drainage and alluvial features suggest tectonic control of the southeastern escarpment of the Benton Hills. The authors propose the coincidence of geologic structures and landforms resembles tectonically active alluvial basin margins, with the Benton Hills southeastern margin representing a fault block uplift escarpment. Future seismic reflection, drilling and trenching studies are planned to determine if the escarpment is fault controlled and of recent origin.

  12. New insights on Southern Coyote Creek Fault and Superstition Hills Fault

    NASA Astrophysics Data System (ADS)

    van Zandt, A. J.; Mellors, R. J.; Rockwell, T. K.; Burgess, M. K.; O'Hare, M.

    2007-12-01

    Recent field work has confirmed an extension of the southern Coyote Creek (CCF) branch of the San Jacinto fault in the western Salton trough. The fault marks the western edge of an area of subsidence caused by groundwater extraction, and field measurements suggest that recent strike-slip motion has occurred on this fault as well. We attempt to determine whether this fault connects at depth with the Superstition Hills fault (SHF) to the southeast by modeling observed surface deformation between the two faults measured by InSAR. Stacked ERS (descending) InSAR data from 1992 to 2000 is initially modeled using a finite fault in an elastic half-space. Observed deformation along the SHF and Elmore Ranch fault is modeled assuming shallow (< 5 km) creep. We test various models to explain surface deformation between the two faults.

  13. Active fault traces along Bhuj Fault and Katrol Hill Fault, and trenching survey at Wandhay, Kachchh, Gujarat, India

    NASA Astrophysics Data System (ADS)

    Morino, Michio; Malik, Javed N.; Mishra, Prashant; Bhuiyan, Chandrashekhar; Kaneko, Fumio

    2008-06-01

    Several new active fault traces were identified along Katrol Hill Fault (KHF). A new fault (named as Bhuj Fault, BF) that extends into the Bhuj Plain was also identified. These fault traces were identified based on satellite photo interpretation and field survey. Trenches were excavated to identify the paleoseismic events, pattern of faulting and the nature of deformation. New active fault traces were recognized about 1km north of the topographic boundary between the Katrol Hill and the plain area. The fault exposure along the left bank of Khari River with 10m wide shear zone in the Mesozoic rocks and showing displacement of the overlying Quaternary deposits is indicative of continued tectonic activity along the ancient fault. The E-W trending active fault traces along the KHF in the western part changes to NE-SW or ENE-WSW near Wandhay village. Trenching survey across a low scarp near Wandhay village reveals three major fault strands F1, F2, and F3. These fault strands displaced the older terrace deposits comprising Sand, Silt and Gravel units along with overlying younger deposits from units 1 to 5 made of gravel, sand and silt. Stratigraphic relationship indicates at least three large magnitude earthquakes along KHF during Late Holocene or recent historic past.

  14. Cross-fault triggering in the November 1987 Superstition Hills earthquake sequence, southern California

    SciTech Connect

    Hudnut, K.W.; Pacheco, J. Columbia University, New York, NY ); Seeber, L. )

    1989-02-01

    Two large strike-slip ruptures 11.4 hours apart occurred on intersecting, nearly orthogonal, vertical faults during the November 1987 Superstition Hills earthquake sequence in southern California. This sequence is the latest in a northwestward progression of earthquakes (1979, 1981, and 1987) rupturing a set of parallel left-lateral cross-faults that trend northeast between the Brawley seismic zone and Superstition Hills fault, a northwest trending main strand of the San Jacinto fault zone. The first large event (M{sub s} = 6.2) in the 1987 sequence ruptured the Elmore Ranch fault, a cross-fault that strikes northeasterly between the Brawley seismic zone and the Superstition Hills main fault. The second event (M{sub s} = 6.6) initiated its rupture at the intersection of the cross-fault and main fault and propagated towards the southeast along the main fault. The following hypotheses are advanced; (1) slip on the cross-fault locally decreased normal stress on the main fault, and triggered the main fault rupture after a delay; and (2) the delay was caused by fluid diffusion. It is inferred that the observed northwestward progression of ruptures on cross-faults may continue. The next cross-fault expected to rupture intersects both the San Andreas fault and the San Jacinto fault zone. The authors hypothesize that rupture of this cross-fault may trigger rupture on either of these main faults by a mechanism similar to that which occurred in the Superstition Hills earthquake sequence.

  15. Slip on the Suckling Hills splay fault during the 1964 Alaska earthquake

    NASA Astrophysics Data System (ADS)

    Chapman, James B.; Elliott, Julie; Doser, Diane I.; Pavlis, Terry L.

    2014-12-01

    The Suckling Hills in southern Alaska experienced localized, anomalously large coseismic uplift in the Mw 9.2, 1964 Alaska earthquake. Large uplift at the Suckling Hills can be explained by increased slip, or an asperity, on the Alaska-Aleutian megathrust; however, this paper suggests that increased uplift may be a result of slip on the Suckling Hills splay fault. We present a series of models that demonstrate how the inclusion of the Suckling Hills fault improves the fit between modeled vertical displacement and measured coseismic uplift in comparison to slip on the Alaska-Aleutian megathrust alone. Our results suggest that ~ 3 m of average slip on the Suckling Hills fault during the 1964 earthquake can help explain the large coseismic uplift data. These results are consistent with recent studies indicating Pleistocene slip on the Suckling Hills fault and together highlight the potential seismic and tsunami risk associated with this segment of the Alaskan subduction complex.

  16. Inverting measurements of surface slip on the Superstition Hills fault

    USGS Publications Warehouse

    Boatwright, J.; Budding, K.E.; Sharp, R.V.

    1989-01-01

    We derive and test a set of inversions of surface-slip measurements based on the empirical relation u(t)=uf/(1 + T/t)c proposed by Sharp and Saxton (1989) to estimate the final slip uf, the power-law exponent c, and the power-law duration T. At short times, Sharp's relation behaves like the simple power law, u(t)~u1tc, where u1 is the initial slip, that is, the slip at 1 day after the earthquake. At long times, the slip approaches the final slip asymptotically. The inversions are designed in part to exploit the accuracy of measurements of differential slip; that is, measurements of surface slip which are made relative to a set of nails or stakes emplaced after the earthquake. We apply the inversions to slip measurements made at 53 sites along the Superstition Hills fault for the 11 months following the M=6.2 and 6.6 earthqakes of 24 November 1987. -from Authors

  17. Barriers to faulting in the Basin-Range province: evidence from the Sou Hills transverse block

    SciTech Connect

    Fonseca, J.E.

    1985-01-01

    Transverse structural blocks may inhibit the propagation of fault ruptures in the Basin-Range province. The Sou Hills, between Dixie and Pleasant Valleys, is a block of uplifted Tertiary bedrock transverse to the NNE-SSW trend of the central Nevada seismic belt. Three lines of evidence indicate that offset due to normal faulting is much less in the Sou Hills compared to adjacent segments of the seismic belt. First, estimates of total late Cenozoic offsets of pre-extension basalts show that the total offset is less in the Sou Hills. Second, analyses of landforms that reflect rates of relative uplift show that Quaternary tectonic activity on range-bounding faults declines where faults join the Sou Hills. Third, measurements of late Quaternary fault scarps show that individual rupture segments in the Sou Hills are shorter in length and have smaller displacements compared to the nearly continuous ruptures of several meters offset found along the Tobin and Stillwater Ranges to the north and south. The Sou Hills rupture pattern is distinctive: ruptures are dispersed over a wide zone rather than being concentrated along well-defined range fronts. Normal faulting patterns produced by the 1915 Pleasant Valley, Nevada and the 1983 Borah Peak, Idaho earthquakes indicate that a discontinuous, spatially dispersed faulting style typifies ruptures which die out in transverse bedrock features. These historic analogues support a model for prehistoric faulting in which ruptures have repeatedly died out in the Sou Hills. Transverse blocks such as the Sou Hills appear to present barriers to propagating ruptures.

  18. Shallow seismic imaging of folds above the Puente Hills blind-thrust fault, Los Angeles, California

    USGS Publications Warehouse

    Pratt, T.L.; Shaw, J.H.; Dolan, J.F.; Christofferson, S.A.; Williams, R.A.; Odum, J.K.; Plesch, A.

    2002-01-01

    High-resolution seismic reflection profiles image discrete folds in the shallow subsurface (<600 m) above two segments of the Puente Hills blind-thrust fault system, Los Angeles basin, California. The profiles demonstrate late Quaternary activity at the fault tip, precisely locate the axial surfaces of folds within the upper 100 m, and constrain the geometry and kinematics of recent folding. The Santa Fe Springs segment of the Puente Hills fault zone shows an upward-narrowing kink band with an active anticlinal axial surface, consistent with fault-bend folding above an active thrust ramp. The Coyote Hills segment shows an active synclinal axial surface that coincides with the base of a 9-m-high scarp, consistent with tip-line folding or the presence of a backthrust. The seismic profiles pinpoint targets for future geologic work to constrain slip rates and ages of past events on this important fault system.

  19. GPS measurements of deformation associated with the 1987 Superstition Hills earthquake: Evidence for conjugate faulting

    NASA Astrophysics Data System (ADS)

    Larsen, Shawn; Reilinger, Robert; Neugebauer, Helen; Strange, William

    Large station displacements observed from Imperial Valley Global Positioning System (GPS) campaigns are attributed to the November 24, 1987 Superstition Hills earthquake sequence. Thirty sites from a 42 station GPS network established in 1986 were reoccupied during 1988 and/or 1990. Displacements at three sites within 3 kilometers of the surface rupture approach 0.5 m. Eight additional stations within 20 km of the seismic zone are displaced at least 10 cm. This is the first occurrence of a large earthquake (M(sub S) 6.6) within a preexisting GPS network. Best-fitting uniform slip models of rectangular dislocations in an elastic half-space indicate 130 + or - 8 cm right-lateral displacement along the northwest-trending Superstition Hills fault and 30 + or - 10 cm left-lateral displacement along the conjugate northeast-trending Elmore Ranch fault. The geodetic moments are 9.4 x 10(exp 25) dyne-cm and 2.3 x 10(exp 25) dyne-cm for the Superstition Hills and Elmore Ranch faults, respectively, consistent with teleseismic source parameters. The data also suggest the post seismic slip along the Superstition Hills fault is concentrated at shallow depths. Distributed slip solutions using Singular Value Decomposition indicate near uniform displacement along the Elmore Ranch fault and concentrated slip to the northwest and southeast along the Superstition Hills fault. A significant component of non-seismic displacement is observed across the Imperial Valley, which is attributed in part to interseismic plate-boundary deformation.

  20. GPS measurements of deformation associated with the 1987 Superstition Hills earthquake: Evidence for conjugate faulting

    NASA Technical Reports Server (NTRS)

    Larsen, Shawn; Reilinger, Robert; Neugebauer, Helen; Strange, William

    1991-01-01

    Large station displacements observed from Imperial Valley Global Positioning System (GPS) campaigns are attributed to the November 24, 1987 Superstition Hills earthquake sequence. Thirty sites from a 42 station GPS network established in 1986 were reoccupied during 1988 and/or 1990. Displacements at three sites within 3 kilometers of the surface rupture approach 0.5 m. Eight additional stations within 20 km of the seismic zone are displaced at least 10 cm. This is the first occurrence of a large earthquake (M(sub S) 6.6) within a preexisting GPS network. Best-fitting uniform slip models of rectangular dislocations in an elastic half-space indicate 130 + or - 8 cm right-lateral displacement along the northwest-trending Superstition Hills fault and 30 + or - 10 cm left-lateral displacement along the conjugate northeast-trending Elmore Ranch fault. The geodetic moments are 9.4 x 10(exp 25) dyne-cm and 2.3 x 10(exp 25) dyne-cm for the Superstition Hills and Elmore Ranch faults, respectively, consistent with teleseismic source parameters. The data also suggest the post seismic slip along the Superstition Hills fault is concentrated at shallow depths. Distributed slip solutions using Singular Value Decomposition indicate near uniform displacement along the Elmore Ranch fault and concentrated slip to the northwest and southeast along the Superstition Hills fault. A significant component of non-seismic displacement is observed across the Imperial Valley, which is attributed in part to interseismic plate-boundary deformation.

  1. Using UAVSAR to Estimate Creep Along the Superstition Hills Fault, Southern California

    NASA Astrophysics Data System (ADS)

    Donnellan, A.; Parker, J. W.; Pierce, M.; Wang, J.

    2012-12-01

    UAVSAR data were first acquired over the Salton Trough region, just north of the Mexican border in October 2009. Second passes of data were acquired on 12 and 13 April 2010, about one week following the 5 April 2010 M 7.2 El Mayor - Cucapah earthquake. The earthquake resulted in creep on several faults north of the main rupture, including the Yuha, Imperial, and Superstition Hills faults. The UAVSAR platform acquires data about every six meters in swaths about 15 km wide. Tropospheric effects and residual aircraft motion contribute to error in the estimation of surface deformation in the Repeat Pass Interferometry products. The Superstition Hills fault shows clearly in the associated radar interferogram; however, error in the data product makes it difficult to infer deformation from long profiles that cross the fault. Using the QuakeSim InSAR Profile tool we extracted line of site profiles on either side of the fault delineated in the interferogram. We were able to remove much of the correlated error by differencing profiles 250 m on either side of the fault. The result shows right-lateral creep of 1.5±.4 mm along the northern 7 km of the fault in the interferogram. The amount of creep abruptly changes to 8.4±.4 mm of right lateral creep along at least 9 km of the fault covered in the image to the south. The transition occurs within less than 100 m along the fault. We also extracted 2 km long line of site profiles perpendicular to this section of the fault. Averaging these profiles shows a step across the fault of 14.9±.3 mm with greater creep on the order of 20 mm on the northern two profiles and lower creep of about 10 mm on the southern two profiles. Nearby GPS stations P503 and P493 are consistent with this result. They also confirm that the creep event occurred at the time of the El Mayor - Cucapah earthquake. By removing regional deformation resulting from the main rupture we were able to invert for the depth of creep from the surface. Results indicate

  2. Global positioning system measurements of deformations associated with the 1987 Superstition Hills earthquake - Evidence for conjugate faulting

    NASA Astrophysics Data System (ADS)

    Larsen, Shawn; Reilinger, Robert; Neugebauer, Helen; Strange, William

    1992-04-01

    Large station displacements observed from Imperial Valley Global Positioning System (GPS) compaigns are attributed to the November 24, 1987 Superstition Hills earthquake sequence. Thirty sites from a 42 station GPS network established in 1986 were reoccupied during 1988 and/or 1990. Displacements at three sites within 3 kilometers of the surface rupture approach 0.5 m. Eight additional stations within 20 km of the seismic zone are displaced at least 10 cm. This is the first occurrence of a large earthquake (M(sub S) 6.6) within a preexisting GPS network. Best-fitting uniform slip models of rectangular dislocations in an elastic half-space indicate 130 + or - 8 cm right-lateral displacement along the northwest-trending Superstition Hills fault and 30 + or - 10 cm left-lateral displacement along the conjugate northeast-trending Elmore Ranch fault. The geodetic moments are 9.4 x 10 (exp 25) dyne-cm and 2.3 x 10 (exp 25) dyne-cm for the Superstition Hills and Elmore Ranch faults, respectively, consistent with teleseismic source parameters. The data also suggest the post seismic slip along the Superstition Hills fault is concentrated at shallow depths. Distributed slip solutions using Singular Value Decomposition indicate near uniform displacement along the Elmore Ranch fault and concentrated slip to the northwest and southeast along the Superstition Hills fault. A significant component of non-seismic displacement is observed across the Imperial Valley, which is attributed in part to interseismic plate-boundary deformation.

  3. Global positioning system measurements of deformations associated with the 1987 Superstition Hills earthquake - Evidence for conjugate faulting

    NASA Technical Reports Server (NTRS)

    Larsen, Shawn; Reilinger, Robert; Neugebauer, Helen; Strange, William

    1992-01-01

    Large station displacements observed from Imperial Valley Global Positioning System (GPS) compaigns are attributed to the November 24, 1987 Superstition Hills earthquake sequence. Thirty sites from a 42 station GPS network established in 1986 were reoccupied during 1988 and/or 1990. Displacements at three sites within 3 kilometers of the surface rupture approach 0.5 m. Eight additional stations within 20 km of the seismic zone are displaced at least 10 cm. This is the first occurrence of a large earthquake (M(sub S) 6.6) within a preexisting GPS network. Best-fitting uniform slip models of rectangular dislocations in an elastic half-space indicate 130 + or - 8 cm right-lateral displacement along the northwest-trending Superstition Hills fault and 30 + or - 10 cm left-lateral displacement along the conjugate northeast-trending Elmore Ranch fault. The geodetic moments are 9.4 x 10 (exp 25) dyne-cm and 2.3 x 10 (exp 25) dyne-cm for the Superstition Hills and Elmore Ranch faults, respectively, consistent with teleseismic source parameters. The data also suggest the post seismic slip along the Superstition Hills fault is concentrated at shallow depths. Distributed slip solutions using Singular Value Decomposition indicate near uniform displacement along the Elmore Ranch fault and concentrated slip to the northwest and southeast along the Superstition Hills fault. A significant component of non-seismic displacement is observed across the Imperial Valley, which is attributed in part to interseismic plate-boundary deformation.

  4. Formation of the Red Hills Ultramafic Massif during Subduction Initiation along an Oceanic Transform Fault

    NASA Astrophysics Data System (ADS)

    Tikoff, B.; Stewart, E. D.; Newman, J.; Lamb, W. M.

    2015-12-01

    The Red Hills ultramafic massif in the South Island, New Zealand, is part of the Dun Mountain Ophiolite Belt (DMOB). The DMOB was created at the onset of subduction in a forearc setting in the Middle Permian, and it likely formed immediately prior to the establishment of a magmatic arc along the New Zealand and Australian portions of the Gondwanan margin. The Red Hills ultramafic massif records a two-stage history of high temperature mantle flow during subduction initiation along the Gondwanan margin. Initial deformation was homogeneous and fabrics are constrictional. Kilometer-scale deformation zones, part of the second stage of deformation, overprinted the early homogeneous fabric throughout the western portion of the massif. Timing of all high-temperature mantle deformation in the Red Hills was between 285 and 274 Ma during subduction initiation based on the earliest ages of igneous activity in adjacent volcanic rocks, and a new U-Pb zircon age of 274.55±0.43 Ma from a cross-cutting dike. We present a kinematic model to explain the occurrence of the constructional fabrics during subduction initiation, and find that the three-dimensional boundary conditions for deformation in the incipient mantle wedge must have been transtensional, with a dominant trench-parallel component of motion. Such a scenario indicates subduction likely initiated along an active oceanic transform fault. We test this model by kinematically restoring the Red Hills ultramafics to their Permian orientation, and find the consistent elongation direction of the constructional fabrics was oriented nearly parallel to the trench. Stage 2 deformation zones were variably oriented, but all accommodated normal motion. These results support a model where the incipient mantle wedge was undergoing highly oblique transtension, and the lack of evidence for contraction suggests the onset of subduction along the Permian margin of New Zealand occurred along a transform fault due to spontaneous, density driven

  5. Surface displacement on the Imperial and Superstition Hills faults triggered by the Westmorland, California, earthquake of 26 April 1981

    USGS Publications Warehouse

    Sharp, R.V.; Lienkaemper, J.J.; Rymer, M.J.

    1982-01-01

    Parts of the Imperial and the Superstition Hills faults moved right-laterally at the ground surface at the time of or shortly following the ML 5.6 Westmorland earthquake of 26 April 1981. The displacements occurred prior to any significant aftershocks on either fault and thus are classed as sympathetic. Although the main shock was located in an exceptionally seismogenic part of Imperial Valley, about 20 km distant from either fault, no clear evidence of surface faulting has yet been found in the epicentral area. Horizontal displacement on the Imperial and Superstition Hills faults, southeast and southwest of the epicenter, respectively, reached maxima of 8 mm and 14 mm, and the discontinuous surface ruptures formed along approximately equal lengths of northern segments of the two structures (16.8 km and 15.7 km, respectively). The maximum vertical component of slip on the Imperial fault, 6 ram, was observed 3.4 km north of the point of largest horizontal slip. Vertical movement on the Superstition Hills fault was less than 1 mm. No new displacement was found along the traces of the Brawley fault zone, the San Andreas fault, or the part of the Coyote Creek fault that slipped during the 1968 Borrego Mountain earthquake. A careful search in the epicentral area of the main shock failed to locate any definite evidence of surface faulting. Concentrations of late aftershocks north and northeast of Calipatria near the southeastward projection of the San Andreas fault occurred mostly after our field check; this area was not investigated.

  6. Structural, Geochemical, and Thermal Evolution of the Southen San Andreas and Parallel Subsidiary Faults in the Mecca Hills, Southern California

    NASA Astrophysics Data System (ADS)

    Moser, A. C.; Evans, J. P.; Ault, A. K.; Janecke, S. U.; Keighley Bradbury, K.; Clausnitzer, S. M.

    2015-12-01

    The Mecca Hills, Southern California, is a 30 km-long, 8 km-wide north-plunging anticlinorium related to transpression and dextral/dextral normal faults along the southern San Andreas Fault (SAF). Although an iconic area for studying transpressional deformation and the Late Cenozoic sedimentary record, the long-term history of faulting, significance and kinematics of the subsidiary faults, and relationship between these faults and the main trace of the SAF remain unclear. We examine the petrologic, kinematic, and timing relationships between 4 subsidiary faults and related damage zones that parallel the SAF to evaluate relationships with the SAF and the Eastern California Shear Zone. At least 6 major faults cut the Mesozoic to Late Tertiary crystalline and sedimentary rocks in the Mecca Hills, including the SAF. Hematite- and clay-coated fracture and slip surfaces are common in damage zones of the subsidiary faults. Slip surface orientation data of hematite-coated surfaces in the Painted Canyon Fault damage zone cluster at 110°, 65° SW and at 196°, 90° W. Similar surfaces in the Platform Fault damage zone cluster at 049°, 69 SE° and 003°, 83° E. Clay-coated slip surfaces in the Hidden Springs Fault damage zone cluster at 195°, 53° W and 196°, 11° W. Multiple slip vector orientations are observed on a single fault surface, consistent with oblique and dip-slip motion on faults in the Mecca Hills. Iridescent hematite and smooth clay surfaces suggest frictional heating on these surfaces, possibly from seismic slip. Preliminary scanning electron microscopy data reveal thin (10s-100s of μm), brecciated hematite slip surfaces. The specular hematite appears originally syn-tectonic and subsequently reworked with host rock and comminuted in multiple slip events. We apply hematite and apatite (U-Th)/He dating from the fault surface and host rock, respectively, to constrain fault thermal evolution and evaluate hematite (U-Th)/He dates as recording hematite

  7. Soufrière Hills eruption, Montserrat, 1995 - 1997: volcanic earthquake locations and fault plane solutions

    USGS Publications Warehouse

    Aspinall, W.P.; Miller, A.D.; Lynch, L.L.; Latchman, J.L.; Stewart, R.C.; White, R.A.; Power, J.A.

    1998-01-01

    A total of 9242 seismic events, recorded since the start of the eruption on Montserrat in July 1995, have been uniformly relocated with station travel-time corrections. Early seismicity was generally diffuse under southern Montserrat, and mostly restricted to depths less than 7 km. However, a NE-SW alignment of epicentres beneath the NE flank of the volcano emerged in one swarm of volcano-tectonic earthquakes (VTs) and later nests of VT hypocentres developed beneath the volcano and at a separated location, under St. George's Hill. The overall spatial distribution of hypocentres suggests a minimum depth of about 5 km for any substantial magma body. Activity associated with the opening of a conduit to the surface became increasingly shallow, with foci concentrated below the crater and, after dome building started in Fall 1995, VTs diminished and repetitive swarms of ‘hybrid’ seismic events became predominant. By late-1996, as magma effusion rates escalated, most seismic events were originating within a volume about 2 km diameter which extended up to the surface from only about 3 km depth - the diminution of shear failure earthquakes suggests the pathway for magma discharge had become effectively unconstricted. Individual and composite fault plane solutions have been determined for a few larger earthquakes. We postulate that localised extensional stress conditions near the linear VT activity, due to interaction with stresses in the overriding lithospheric plate, may encourage normal fault growth and promote sector weaknesses in the volcano.

  8. Textural and Rb-Sr isotopic evidence for late Paleozoic mylonitization within the Honey Hill fault zone southeastern Connecticut

    SciTech Connect

    O'Hara, K.D.; Gromet, L.P.

    1983-09-01

    A petrographic and Rb-Sr isotopic study of rocks within and near the Honey Hill fault zone places important constraints on its history of movement. Rb-Sr apparent ages for micas and plagioclase from these rocks have been reset and range from Permian to Triassic, considerably younger than the minimum stratigraphic age (Ordovician) of the rocks studied or of Acadian (Devonian) regional metamorphism. Permian Rb-Sr ages of dynamically recrystallized muscovite date the development of mylonite fabric. An older age is precluded by the excellent preservation of unrecovered quartz, which indicates that these rocks did not experience temperatures high enough to anneal quartz or thermally reset Rb-Sr isotopic systems in muscovite since the time of mylonitization. Metamorphic mineral assemblages and mineral apparent ages in rocks north of the fault zone indicate recrystallization under similar upper greenschist-lower amphibolite grade conditions during Permian to Triassic time. Collectively these results indicate that the Honey Hill fault zone was active during the Late Paleozoic and that ductile deformation and metamorphism associated with the Alleghanian orogeny extend well into southern Connecticut. An Alleghanian age for mylonitization within the Honey Hill fault zone suggests it should be considered as a possible site for the major Late Paleozoic strike-slip displacements inferred from paleomagnetic studies for parts of coastal New England and maritime Canada.

  9. Seismic constraints and coulomb stress changes of a blind thrust fault system, 1: Coalinga and Kettleman hills, California

    USGS Publications Warehouse

    Lin, Jian; Stein, Ross S.

    2006-01-01

    This report reviews the seismicity and surface ruptures associated with the 1982-1985 earthquake sequence in the Coalinga region in California, and the role of Coulomb stress in triggering the mainshock sequence and aftershocks. The 1982-1985 New Idria, Coalinga, and Kettleman Hills earthquakes struck on a series of west-dipping, en echelon blind thrust faults. Each earthquake was accompanied by uplift of a Quaternary anticline atop the fault, and each was accompanied by a vigorous aftershock sequence. Aftershocks were widely dispersed, and are seen above and below the thrust fault, as well as along the up-dip and down-dip projection of the main thrust fault. For the Coalinga and Kettleman Hills earthquakes, high-angle reverse faults in the core of the anticlines are evident in seismic reflection profiles, and many of these faults are associated with small aftershocks. The shallowest aftershocks extended to within 3-4 km of the ground surface. There is no compelling evidence for aftershocks associated with flexural slip faulting. No secondary surface rupture was found on any of the anticlines. In contrast, the 1983 Nu?ez rupture struck on a high-angle reverse fault 10 km west of the Coalinga epicenter, and over a 40-80-day period, up to 1 m of oblique surface slip occurred. The slip on this Holocene fault likely extended from the ground surface to a depth of 8-10 km. We argue that both the Nu?ez and Kettleman earthquakes were triggered by stresses imparted by the Coalinga mainshock, which was the largest of the four events in the sequence.

  10. Thermochronology of fault rocks from the mid-Miocene South Virgin-White Hills detachment, Arizona and Nevada

    NASA Astrophysics Data System (ADS)

    Verdel, C.; van der Pluijm, B. A.; Niemi, N. A.

    2009-12-01

    One of the most prominent low-angle normal fault systems in the Basin and Range province of the western U.S. is the ~100 km-long South Virgin-White Hills detachment. Multiple low-temperature thermochronometers have been used to document rapid Miocene exhumation of the footwall of this detachment, most notably within the Gold Butte block of southern Nevada. Less attention has been paid to the actual faults that comprise the detachment system, one of which (the Salt Spring fault) is very well-exposed over an along-strike distance of about 5 km just south of Lake Mead. In this location, the fault dips ~25° and separates Proterozoic crystalline rocks in the footwall from Tertiary gravels and volcanic rocks in the hanging wall. At one exceptional outcrop, the fault consists of a 9 m-thick stratified zone of brecciated granite in a clay matrix (fault breccia), overlain by a relatively thin (<1 m) layer of finer-grained, foliated, clay-rich fault gouge that is in direct contact with overlying Tertiary gravels. Clay minerals are a minor constituent of the crystalline footwall rocks but are abundant in the fault zone. We utilized apatite fission track and illite/muscovite 40Ar/39Ar thermochronology to investigate the thermal evolution of the fault gouge. Apatite grains entrained in the gouge have fission track ages of ~15 Ma, comparable to previously published apatite fission track ages from structurally deep parts of the Gold Butte block and the immediate footwall of the Salt Spring fault, near the fault rock sampling site. Encapsulated 40Ar/39Ar data from micron-scale size fractions of the gouge yield staircase-shaped step-heating spectra that reach maximum ages of 80 to 110 Ma. The primary K-bearing phases in these size fractions are illite and muscovite. In structurally deep parts of the Gold Butte block, previously published muscovite 40Ar/39Ar ages are ~90 Ma. We interpret the staircase-shaped 40Ar/39Ar spectra of the fault gouge 1) to indicate the presence of

  11. Identification of an active fault in the Japanese Alps from DEM-based hill shading

    NASA Astrophysics Data System (ADS)

    Oguchi, Takashi; Aoki, Tatsuto; Matsuta, Nobuhisa

    2003-08-01

    Shaded-relief images created from digital elevation models (DEMs) are helpful in identifying faults in rugged mountains. Unlike airphoto interpretation, the method enhances lineaments by simulating topographic illumination under varied light directions. Interpretation of shaded-relief images of the Japanese Alps led to the discovery of a lineament unrelated to bedrock structure. Field surveys and analysis of large-scale maps and airphotos reveal the lineament to be a fault with high rates of vertical and lateral slip. The new fault is the southernmost segment of a known adjacent fault, and the rate and direction of its slip provide fresh insight into the late Quaternary history of the fault system. Because previous research mistook the fault scarp for a fluvial terrace scarp, discovery of the fault also changed the correlation of river terraces in the Northern Japanese Alps. The new corrections affect Pleistocene glacial chronology in the upstream area.

  12. Erosion in the Mecca Hills: using GIS to investigate potential erosion factors along the southern San Andreas Fault.

    NASA Astrophysics Data System (ADS)

    Maneerat, P.; Reinen, L. A.; Fukutaki, K. G.; Rittiron, S.; Mejias, R.

    2015-12-01

    The Mecca Hills (MH) occur in a region of transpression along the southern San Andreas Fault. These geomorphic features are a result of the interplay between uplift and erosion. The MH are mostly covered by uniform sedimentary rocks with > 70% the Pliocene-Pleistocene Palm Spring Formation, > 20% Quaternary sediments and a minor amount of crystalline rock suggesting similar denudation rate over the region. However, Gray et al. (Quat. Sci. Rev. 2014) found a wide range of denudation rates (20 to 150 m/My) by using 10Be concentrations in active-channel alluvial sediment. We investigate potential causes of erosion to understand the variation of the denudation rate and examine the maturity of watersheds in the MH. We use ArcGIS to find the best geomorphic proxy for the published erosion rates by considering elevation, lithology, mean slope and active faults by using the index value method proposed by Gray et al. We apply the best geomorphic proxy to the overall MH to predict the spatial variation of erosion rate over the region. We use hypsometric integral (HI) and basin elongation ratio (BER) to study the maturity of the overall MH watersheds. We found that active faults are the main factor influencing erosion in the MH. Drainage basins located closer to active faults have higher erosion rates than others. Most watersheds are in a mature stage of the erosion cycle. Overall, the watersheds in the central MH are in a more youthful stage of the erosion cycle than the ones to the north and south. BER values suggest that the watersheds in the central MH formed earlier and have more time to develop their stream networks. Although watersheds in the central MH formed earlier than the others, their stage of erosion cycle is more youthful due to the proximity of active faults enhancing local erosion rates.

  13. Geomorphic LiDAR Mapping of Latest Pleistocene Deposits and the Western Extent of the Fickle Hill Fault, Arcata, Northern California

    NASA Astrophysics Data System (ADS)

    Vermeer, J.; Hemphill-Haley, M.

    2013-12-01

    I incorporated high-resolution LiDAR elevation data to map the geomorphology of faulted late Pleistocene marine terraces in coastal northwestern California near Arcata. The study area is located within the onland fold and thrust belt of the southern Cascadia subduction zone. I identified multiple splays of the Fickle Hill fault, an active, northwest-striking, southwest vergent thrust zone within the broader Mad River fault zone. I identified five splays of the Fickle Hill fault within downtown Arcata. Northwest of the town I identified three possible traces in younger uplifted marine terrace surfaces. Correlation of marine formed geomorphological units to sea level curves enabled me to estimate ages for them. This in turn allowed me to approximate the age of displacement on some of splays of the fault. Preliminary assignments of ages 100 ka for a prominent fault marine terrace, and 80ka delta/fan complex and recessional platform to between 75 and 80 ka provide a regional uplift rate for the Arcata area of 0.2 mm/yr. The northern splay of the fault has not deformed the marine terrace thus has not been active in ca. 100 ka. The middle splay has had ~5 m of total vertical separation since formation of the marine terrace; about 4m of that offset occurred between 100 and 80 ka. The southern splay, an associated antithetic splay and the middle splay of the fault all have had displacement since the recessional platform was formed about 75 ka.

  14. Geophysical Survey of Proposed Construction Site with Possible Faulting, East San Francisco Bay Hills, California

    NASA Astrophysics Data System (ADS)

    Galvin, J. L.; Deqiang, C.; Abimbola, A.; Shuler, S.; Hayashi, K.; Fox, J.; Craig, M. S.; Strayer, L. M.; Drumm, P.

    2015-12-01

    We conducted a geophysical study at a site proposed for a new dorm building prior to trenching planned as part of a separate fault investigation study. The study area was located on the south side of the CSU East Bay campus, roughly 100 - 300 m SSE of the current dorm complex. In addition to its proximity to the Hayward Fault, several smaller faults have been previously mapped within the proposed location, including the East and West Dibblee Faults. These faults are thought to represent contacts between the Leona Rhyolite and the Knoxville Formation. Data acquisition included seismic, resistivity, and GPS data collected in an effort to develop a better understanding of the geological and structural profile of this area, including the location of lithologic contacts, faults, and the thickness of soil and fill. Geophysical profiles were collected over the locations of future trenches. The survey included geophysical lines that were located coincident with two planned trenching sites, which were chosen to intersect mapped faults. Survey positions were recorded using differential GPS. Seismic refraction and MASW (multichannel analysis of surface waves) surveys were performed over two of the planned trench sites using a 48-channel seismographic system with 4.5 Hz geophones and a 10-lb sledgehammer. For one of the lines, geophones were spaced every 3 m with a total spread length of 141 m and a shot spacing of 9 m. For the second line, geophones were spaced every 4 m with a total spread length of 188 m. Shots were taken every 12 m. Resistivity surveys were also performed along one of the line locations using both a capacitively-coupled dipole (CCD) system and 48-electrode system. Geospatial data for the survey area were compiled, including 0.3 m color orthoimagery and vector line files for geologic unit boundaries and presumed fault locations. The products of this study will include the geophysical response of geologic formations, location of unit contacts and faults

  15. Progressive overprinting of normal fault systems and their role in Tertiary exhumation of the East Humboldt-Wood Hills Metamorphic Complex northeast Nevada

    NASA Astrophysics Data System (ADS)

    Mueller, Karl J.; Snoke, Arthur W.

    1993-01-01

    Low- and high-angle, normal-sense faults present along the northern margin of the East Humboldt-Wood Hills metamorphic complex record a protracted history of episodic extensional unroofing. The earliest extension associated with the exhumation of the metamorphic complex occurred in the mid-Eocene (about 50 Ma) during slip along the west-rooted Wells Peak fault. Subsequent extension developed during movement along the east-rooted Black Mountain fault system in the late Eocene (about 35 Ma). Continued exhumation of the high-grade metamorphic rocks, occurred during the late Oligocene to early Miocene (about 29-23 Ma) along a west-rooted, normal-sense, plastic-to-brittle shear zone exposed along the length of the East Humboldt Range and much of the Ruby Mountains. The mylonitic shear zone, Wells Peak fault, and Black Mountain fault system were all overprinted by the west-rooted, low- to high-angle Mary's River fault system which was active from mid-Miocene to Holocene. Broadly coeval extension in the Windermere Hills was also accommodated by the development of high-angle, north and east dipping normal faults between approximately 35-12 Ma and 12-10 Ma.

  16. Aerial photographic interpretation of lineaments and faults in late Cenozoic deposits in the eastern parts of the Saline Valley 1:100, 000 quadrangle, Nevada and California, and the Darwin Hills 1:100, 000 quadrangle, California

    SciTech Connect

    Reheis, M.C.

    1991-09-01

    Faults and fault-related lineaments in Quaternary and late Tertiary deposits in the southern part of the Walker Lane are potentially active and form patterns that are anomalous compared to those in most other areas of the Great Basin. Two maps at a scale of 1:100,000 summarize information about lineaments and faults in the area around and southwest of the Death Valley-Furnace Creek fault system based on extensive aerial-photo interpretation, limited field interpretation, limited field investigations, and published geologic maps. There are three major fault zones and two principal faults in the Saline Valley and Darwin Hills 1:100,000 quadrangles. (1) The Death Valley-Furnace Creek fault system and (2) the Hunter Mountain fault zone are northwest-trending right-lateral strike-slip fault zones. (3) The Panamint Valley fault zone and associated Towne Pass and Emigrant faults are north-trending normal faults. The intersection of the Hunter Mountain and Panamint Valley fault zones is marked by a large complex of faults and lineaments on the floor of Panamint Valley. Additional major faults include (4) the north-northwest-trending Ash Hill fault on the west side of Panamint Valley, and (5) the north-trending range-front Tin Mountain fault on the west side of the northern Cottonwood Mountains. The most active faults at present include those along the Death Valley-Furnace Creek fault system, the Tin Mountain fault, the northwest and southeast ends of the Hunter Mountain fault zone, the Ash Hill fault, and the fault bounding the west side of the Panamint Range south of Hall Canyon. Several large Quaternary landslides on the west sides of the Cottonwood Mountains and the Panamint Range apparently reflect slope instability due chiefly to rapid uplift of these ranges. 16 refs.

  17. A silent Mw 4.7 slip event of October 2006 on the Superstition Hills fault, southern California

    NASA Astrophysics Data System (ADS)

    Wei, Meng; Sandwell, David; Fialko, Yuri

    2009-07-01

    During October 2006, the 20-km-long Superstition Hills fault (SHF) in the Salton Trough, southern California, slipped aseismically, producing a maximum offset of 27 mm, as recorded by a creepmeter. We investigate this creep event as well as the spatial and temporal variations in slip history since 1992 using ERS-1/2 and Envisat satellite data. During a 15-year period, steady creep is punctuated by at least three events. The first two events were dynamically triggered by the 1992 Landers and 1999 Hector Mine earthquakes. In contrast, there is no obvious triggering mechanism for the October 2006 event. Field measurements of fault offset after the 1999 and 2006 events are in good agreement with the interferometric synthetic aperture radar data indicating that creep occurred along the 20-km-long fault above 4 km depth, with most of the slip occurring at the surface. The moment released during this event is equivalent to a Mw 4.7 earthquake. This event produced no detectable aftershocks and was not recorded by the continuous GPS stations that were 9 km away. Modeling of the long-term creep from 1992 to 2007 creep using stacked ERS-1/2 interferograms also shows a maximum creep depth of 2-4 km, with slip tapering with depth. Considering that the sediment thickness varies between 3 km and 5 km along the SHF, our results are consistent with previous studies suggesting that shallow creep is controlled by sediment depth, perhaps due to high pore pressures in the unconsolidated sediments.

  18. UAVSAR observations of triggered slip on the Imperial, Superstition Hills, and East Elmore Ranch Faults associated with the 2010 M 7.2 El Mayor-Cucapah earthquake

    NASA Astrophysics Data System (ADS)

    Donnellan, Andrea; Parker, Jay; Hensley, Scott; Pierce, Marlon; Wang, Jun; Rundle, John

    2014-03-01

    4 April 2010 M 7.2 El Mayor-Cucapah earthquake that occurred in Baja California, Mexico and terminated near the U.S. Mexican border caused slip on the Imperial, Superstition Hills, and East Elmore Ranch Faults. The pattern of slip was observed using radar interferometry from NASA's Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) instrument collected on 20-21 October 2009 and 12-13 April 2010. Right-lateral slip of 36 ± 9 and 14 ± 2 mm occurred on the Imperial and Superstition Hills Faults, respectively. Left-lateral slip of 9 ± 2 mm occurred on the East Elmore Ranch Fault. The widths of the zones of displacement increase northward suggesting successively more buried fault motion to the north. The observations show a decreasing pattern of slip northward on a series of faults in the Salton Trough stepping between the El Mayor-Cucapah rupture and San Andreas Fault. Most of the motion occurred at the time of the M 7.2 earthquake and the UAVSAR observations are consistent with field, creepmeter, GPS, and Envisat observations. An additional 28 ± 1 mm of slip at the southern end of the Imperial Fault over a <1 km wide zone was observed over a 1 day span a week after the earthquake suggesting that the fault continued to slip at depth following the mainshock. The total moment release on the three faults is 2.3 × 1023-1.2 × 1024 dyne cm equivalent to a moment magnitude release of 4.9-5.3, assuming shallow slip depths ranging from 1 to 5 km.

  19. Three-dimensional Geometry of Buried Fold Scarps Associated With Ancient Earthquakes on the Puente Hills Blind Thrust Fault

    NASA Astrophysics Data System (ADS)

    Leon, L. A.; Dolan, J. F.; Hoeft, J. S.; Shaw, J. H.; Hartleb, R. D.

    2003-12-01

    The Puente Hills thrust fault (PHT) is a large blind thrust fault that extends east-west beneath the heart of the metropolitan Los Angeles region (Shaw and Shearer, 1999; Shaw et al., 2003). Christofferson (2002; in prep.) and Dolan et al. (2003) identified four buried fold scarps associated with large (Mw greater than or equal to 7), ancient earthquakes on the PHT beneath the City of Bellflower, in northern Orange County. One of the major outstanding questions regarding this research concerns the subsurface, three-dimensional geometry of these buried scarps. Specifically, we want to determine the extent to which the subsurface geometry of these scarps is controlled by tectonic versus fluvial processes. In order to begin addressing these questions, we drilled a north-south transect of hollow-stem, continuously cored boreholes across the buried fold scarps. This new borehole transect, which comprises six, 20-m-deep boreholes, was drilled parallel to, and ˜ 100 m west of, the original Carfax Avenue transect of Christofferson (2002) and Dolan et al. (2003). The overall pattern of progressive southward thickening of sedimentary units observed in the Carfax borehole transect extends westward to the new transect. Moreover, several key sedimentary contacts that are traceable laterally between the two transects occur at approximately the same depths at all locations along both transects. This three-dimensional data set thus defines several buried fold scarps that extend east-west beneath the study site. These observations confirm that the buried scarps are primarily tectonic, rather than fluvial features.

  20. Geophysical and geochemical characterization of the groundwater system and the role of Chatham Fault in groundwater movement at the Coles Hill uranium deposit, Virginia, USA

    NASA Astrophysics Data System (ADS)

    Gannon, John P.; Burbey, Thomas J.; Bodnar, Robert J.; Aylor, Joseph

    2012-02-01

    The largest undeveloped uranium deposit in the United States, at Coles Hill, is located in the Piedmont region of Pittsylvania County, south-central Virginia, and is hosted in crystalline rocks that are adjacent to and immediately west of Chatham Fault, which separates these crystalline rocks from the metasedimentary rocks of the Danville Triassic Basin (in the east). Groundwater at the site flows through a complex network of interconnected fractures controlled by the geology and structural setting. The role of Chatham Fault in near-surface (<≈200 m) groundwater flow is examined using electrical resistivity profiling, borehole logging, a pumping test, groundwater age dating and water chemistry to determine if the fault represents a permeability barrier or conduit for groundwater flow. The volumetric flow per unit width flowing eastward across the fault is estimated at 0.069-0.17 m2/day. Geochemical data indicate that groundwater in the granitic crystalline rocks represents a mixture of modern and old water, while the Triassic basin contains a possible deeper and older source of water. In regions with shallow water tables, mine dewatering during operation presents significant mining costs. The study's results yield important information concerning the effect that Chatham Fault would have on groundwater flow during Coles Hill mining operations.

  1. Three-dimensional records of surface displacement on the Superstition Hills fault zone associated with the earthquakes of 24 November 1987

    USGS Publications Warehouse

    Sharp, R.V.; Saxton, J.L.

    1989-01-01

    Seven quadrilaterals, constructed at broadly distributed points on surface breaks within the Superstition Hills fault zone, were repeatedly remeasured after the pair of 24 November 1987 earthquakes to monitor the growing surface displacement. Changes in the dimensions of the quadrilaterals are recalculated to right-lateral and extensional components at millimeter resolution, and vertical components of change are resolved at 0.2mm precision. The displacement component data for four of the seven quadrilaterals record the complete fault movement with respect to an October 1986 base. The three-dimensional motion vectors all describe nearly linear trajectories throughout the observation period, and they indicate smooth shearing on their respective fault surfaces. The inclination of the shear surfaces is generally nearly vertical, except near the south end of the Superstition Hills fault zone where two strands dip northeastward at about 70??. Surface displacement on these strands is right reverse. Another kind of deformation, superimposed on the fault displacements, has been recorded at all quadrilateral sites. It consists of a northwest-southeast contraction or component of contraction that ranged from 0 to 0.1% of the quadrilateral lengths between November 1987 and April 1988. -from Authors

  2. Continuity of slip rates over various time scales on the Puente Hills Blind-thrust Fault, Los Angeles, California

    NASA Astrophysics Data System (ADS)

    Bergen, Kristian J.; Shaw, John H.; Leon, Lorraine A.; Dolan, James F.; Pratt, Thomas L.; Ponti, Daniel J.; Barrera, Wendy; Rhodes, Edward J.; Murari, Madhav K.; Owen, Lewis A.

    2014-05-01

    Our study seeks to assess the history of slip on the Los Angeles segment of the Puente Hills blind-thrust fault system (PHT) from its inception through the Holocene by integrating a suite of geological and geophysical datasets. The PHT presents one of the largest seismic hazards in the United States, given its location beneath downtown Los Angeles. It is also well suited to slip rate studies, as fold scarps formed by slip on the PHT at depth have been continually buried by flood deposits from the Los Angeles and San Gabriel Rivers, preserving a record of uplift in the form of growth stratigraphy. We determined uplift from the growth stratigraphy by measuring the difference in sediment thickness across the folded layers. At our study site above the western segment of the PHT, the fold structure was imaged by industry seismic reflection data and a pair of high-resolution (100 to 700 m depth) seismic reflection profiles acquired by the authors for this study using weight drop and small vibrator sources. The industry and high-resolution profiles were stacked, migrated and depth converted using a velocity model based on the stacking velocities and the Southern California Earthquake Center Community Velocity Model. The shallowest layers of growth stratigraphy were geometrically constrained by lithological correlations across a series of cone penetration tests and continuously cored boreholes. Age control was provided by radiocarbon dating, optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL) dating, and sequence-stratigraphic boundaries. Radiocarbon dating was used to constrain individual earthquake event ages in the borehole transect. Using a novel coring procedure, light-protected samples for quartz OSL and feldspar IRSL dating were acquired from a 171-m-deep borehole that we drilled within the growth fold. These samples provided age constraints on growth strata that were tied to prominent seismic reflections and were combined with

  3. Quaternary landscape development, alluvial fan chronology and erosion of the Mecca Hills at the southern end of the San Andreas Fault zone

    USGS Publications Warehouse

    Gray, Harrison J.; Owen, Lewis; Dietsch, Craig; Beck, Richard A.; Caffee, Marc A.; Finkelman, Robert B.; Mahan, Shannon

    2014-01-01

    Quantitative geomorphic analysis combined with cosmogenic nuclide 10Be-based geochronology and denudation rates have been used to further the understanding of the Quaternary landscape development of the Mecca Hills, a zone of transpressional uplift along the southern end of the San Andreas Fault, in southern California. The similar timing of convergent uplifts along the San Andreas Fault with the initiation of the sub-parallel San Jacinto Fault suggest a possible link between the two tectonic events. The ages of alluvial fans and the rates of catchment-wide denudation have been integrated to assess the relative influence of climate and tectonic uplift on the development of catchments within the Mecca Hills. Ages for major geomorphic surfaces based on 10Be surface exposure dating of boulders and 10Be depth profiles define the timing of surface stabilization to 2.6 +5.6/–1.3 ka (Qyf1 surface), 67.2 ± 5.3 ka (Qvof2 surface), and 280 ± 24 ka (Qvof1 surface). Comparison of 10Be measurements from active channel deposits (Qac) and fluvial terraces (Qt) illustrate a complex history of erosion, sediment storage, and sediment transport in this environment. Beryllium-10 catchment-wide denudation rates range from 19.9 ± 3.2 to 149 ± 22.5 m/Ma and demonstrate strong correlations with mean catchment slope and with total active fault length normalized by catchment area. The lack of strong correlation with other geomorphic variables suggests that tectonic uplift and rock weakening have the greatest control. The currently measured topography and denudation rates across the Mecca Hills may be most consistent with a model of radial topographic growth in contrast to a model based on the rapid uplift and advection of crust.

  4. Quaternary landscape development, alluvial fan chronology and erosion of the Mecca Hills at the southern end of the San Andreas Fault zone

    NASA Astrophysics Data System (ADS)

    Gray, Harrison J.; Owen, Lewis A.; Dietsch, Craig; Beck, Richard A.; Caffee, Marc A.; Finkel, Robert C.; Mahan, Shannon A.

    2014-12-01

    Quantitative geomorphic analysis combined with cosmogenic nuclide 10Be-based geochronology and denudation rates have been used to further the understanding of the Quaternary landscape development of the Mecca Hills, a zone of transpressional uplift along the southern end of the San Andreas Fault, in southern California. The similar timing of convergent uplifts along the San Andreas Fault with the initiation of the sub-parallel San Jacinto Fault suggest a possible link between the two tectonic events. The ages of alluvial fans and the rates of catchment-wide denudation have been integrated to assess the relative influence of climate and tectonic uplift on the development of catchments within the Mecca Hills. Ages for major geomorphic surfaces based on 10Be surface exposure dating of boulders and 10Be depth profiles define the timing of surface stabilization to 2.6 +5.6/-1.3 ka (Qyf1 surface), 67.2 ± 5.3 ka (Qvof2 surface), and 280 ± 24 ka (Qvof1 surface). Comparison of 10Be measurements from active channel deposits (Qac) and fluvial terraces (Qt) illustrate a complex history of erosion, sediment storage, and sediment transport in this environment. Beryllium-10 catchment-wide denudation rates range from 19.9 ± 3.2 to 149 ± 22.5 m/Ma and demonstrate strong correlations with mean catchment slope and with total active fault length normalized by catchment area. The lack of strong correlation with other geomorphic variables suggests that tectonic uplift and rock weakening have the greatest control. The currently measured topography and denudation rates across the Mecca Hills may be most consistent with a model of radial topographic growth in contrast to a model based on the rapid uplift and advection of crust.

  5. Seven Post-Pennsylvanian Structural Events in the Dry Hills and Northern Osgood Mountains: Evidence of Late Paleozoic Tectonism and New Getchell Fault Offset Data

    NASA Astrophysics Data System (ADS)

    Taylor, W. J.; Siebenaler, S.; Cashman, P.; Trexler, J.; Davydov, V.

    2008-12-01

    An incomplete understanding of the number and style of deformational events in north-central Nevada complicate economic and stratigraphic studies. To help unravel this structural history, we mapped and measured structures in the Dry Hills, northern Osgood Mountains, Humboldt County, Nevada. This research identified at least seven Pennsylvanian age or younger deformational events. The location was selected because it contains the Roberts Mountain allochthon (RMA), the Pennsylvanian (IP) to Permian (P) age Etchart Formation that was deposited atop the RMA, and the Golconda allochthon (GA). Measured folds and faults provide evidence of at least four deformational events that occurred between emplacement of the RMA and GA. Evidence for Late Paleozoic deformational events was recently well documented in other regional locations, but this location is farther north than previous studies. This research is also important because it provides information about the style and regional extent of these tectonic events. Structural mapping and data analysis reveal that the Etchart Formation contains four upright fold sets (SE-, NNW-, SSW-, NE-trending, in chronologic order) and three fault sets (N-striking normal, ENE-striking thrust, NNE-striking thrust), which may relate to the three youngest fold sets. The relative ages of the folds and faults are constrained via cross-cutting relationships, overprinting, and the oldest fold set being confined solely to the lowest stratigraphic unit within the Etchart Formation. These structures developed prior to and during emplacement of the GA. Two angular unconformities, the C5 and P1 angular unconformities of Trexler et al. (2003), are newly recognized in the area. The SW-trending fold set underlies the C5 unconformity. The P1 unconformity is angular indicating a deformational event and has been confirmed with fusulinid-based ages. The P1 and C5 unconformities correlate to other locations in northern Nevada implying regional scale late

  6. Pre-earthquake displacement and triggered displacement on the Imperial fault associated with the Superstition Hills earthquake of 24 November 1987

    USGS Publications Warehouse

    Sharp, R.V.

    1989-01-01

    Two right-lateral slip events, about 3 weeks apart in November 1987, broke the surface discontinuously along probably similar, nearly 20km lengths of the northern Imperial fault. The first displacement, at about the beginning of November, was accompanied by a surface tilt representing deep vertical motion or distributed strain. The later surface offset was triggered, probably by the second main shock of the 24 November earthquakes located in the Superstition Hills, about 37km northwest of the Imperial fault. Pre-earthquake resurveys of short-length leveling lines indicated combined surface displacement and an eastward tilt at two locations between surveys 7 1/2 months apart and 13 months apart; the tilt at Harris Road during this pre-earthquake interval is modeled as a 1.4cm vertical component of slip deeper than 100m on a 70?? northeastward-dipping fault. Later surveys showed a marked reduction of deep movement in the time period including the triggered slip, and between December 1987 and January 1988, it had ceased. No definite evidence of surface fracturing was found in the Brawley fault zone during either period of time when the Imperial fault moved. -from Authors

  7. Role of Erosion on Closely-Spaced Fault Scarps: High-resolution Laser Scanning Data and Scarp Diffusion Modelling of the Rex Hills Flower Structure, Nevada

    NASA Astrophysics Data System (ADS)

    Baran, R.; Guest, B.; Friedrich, A. M.

    2007-12-01

    Flower structures are often associated with strike-slip faults. Their subsurface geometry is well known but additional information about their geometry and kinematics is also contained in their surface expression, especially in surfaces exhibiting closely-spaced fault scarps. However, detailed surface descriptions of flower structures are rare. Here, we present for the first time topographic profiles extracted from high-resolution digital elevation model (DEM) data using a ground-based laser scanner (Riegl company) to examine the surface expression of a flower structure in great detail. Our study site, the Rex Hills flower structure (40 m high, ~1 km long), is located on the transpressional left-bend between the Pahrump and Amargosa segments of the dextral Stateline fault system (Guest et al., 2007, GSAB). The southern Rex Hills slope exhibits three reverse fault- scarp generations related to three reverse fault branches, respectively. The basal scarp is the youngest and most continuous one. It exhibits five fault segments with an approximately constant displacement along the scarp. The upper two fault-scarp generations are less continuous, and older. The topography of the southern Rex Hills slope also is characterized by alternating valleys and ridges (each ~100 m long) extending perpendicular to the main ridge crest. Our analysis shows that fault scarp morphology varies laterally along this slope. Scarps exposed on ridge crests are typically more numerous (up to 4-5 scarps) and smaller (on average 5 m high), whereas adjacent valleys often exhibit single large (>10 m high) scarps. The larger valley-scarps did not result from the offset across a single fault branch, but resulted from merging of the three scarps mentioned above by enhanced scarp degradation. The preservation potential of small, individual scarps is therefore better on ridge crests relative to adjacent valleys. Assuming a known age of 2 kyrs (Menges et al., 2003, AGU), we examined the spatial

  8. South Virgin-White Hills detachment fault system of SE Nevada and NW Arizona: Applying apatite fission track thermochronology to constrain the tectonic evolution of a major continental detachment fault

    NASA Astrophysics Data System (ADS)

    Fitzgerald, Paul G.; Duebendorfer, Ernest M.; Faulds, James E.; O'Sullivan, Paul

    2009-04-01

    The South Virgin-White Hills detachment (SVWHD) in the central Basin and Range province with an along-strike extent of ˜60 km is a major continental detachment fault system. Displacement on the SVWHD decreases north to south from ˜17 to <6 km. This is accompanied by a change in fault and footwall rock type from mylonite overprinted by cataclasite to chlorite cataclasite and then fault breccia reflecting decreasing fault displacement and footwall exhumation. Apatite fission track (AFT) thermochronology was applied both along-strike and across-strike to assess this displacement gradient. The overall thermal history reflects Laramide cooling (˜75 Ma) and then rapid cooling beginning in the late early Miocene. Age patterns reflect some complexity but extension along the SVWHD appears synchronous with rapid cooling initiated at ˜17 Ma due to tectonic exhumation. Slip rate is more rapid (˜8.6 km/Ma) in the north compared to ˜1 km/Ma in the south. The displacement gradient results from penecontemporaneous along-strike motion and formation of the SVWHD by linkage of originally separate fault segments that have differential displacements and hence differential slip rates. East-west transverse structures likely play a role in linkage of different fault segments. The preextension paleogeothermal gradient is well constrained in the Gold Butte block as 18-20°C/km. We present a new thermochronologic approach to constrain fault dip during slip, treating the vertical exhumation rate and the slip as vectors, with the angle between them used to constrain fault dip during slip through the closure temperature of a particular thermochronometer. AFT data from the western rim of the Colorado Plateau constrain the initiation of timing of cooling associated with the Laramide Orogeny at ˜75 Ma, and a reheating event in the late Eocene/early Oligocene associated with burial by sediments ("rim gravels") most likely shed from the Kingman High to the west of the plateau.

  9. Stratigraphic Record of Basin Formation, Deformation, and Destruction in the Past 2 Ma Along the Southern San Andreas Fault, Mecca Hills, California

    NASA Astrophysics Data System (ADS)

    McNabb, J. C.; Dorsey, R. J.; Housen, B. A.; Messe, G. T.

    2013-12-01

    Sedimentary rocks exposed in the Mecca Hills NE of Coachella Valley, southern California, record vertical crustal motions along the San Andreas (SAF) and associated strike-slip faults. A complex history of subsidence, transport, deposition, and uplift can be interpreted from mapping and measuring of sedimentary rocks, lithofacies analysis, and determination of provenance. Recent field studies suggest a poly-phase history of deformation and sedimentation for the stratigraphy in the Mecca Hills that is likely controlled by evolution of fault zone complexities. The Painted Canyon Fault (PCF), a reverse-oblique strike-slip fault sub-parallel to the SAF, has played a major role in basin formation and inversion over the past ca. 2 Myr. Deformation near the PCF coincides with deviations in fault strike relative to modern plate motion, and sedimentation appears to have been largely controlled by vertical motions accommodated by slip on the PCF. Preliminary magnetostratigraphic work provides tentative depositional age brackets. We infer that the Mecca Conglomerate, a locally derived cobble-boulder conglomerate with ~SSW directed paleoflow, was deposited near the PCF scarp during an early phase of SW-side down slip from ~1.8-1.5 Ma. Next, the Lower Palm Spring Formation, a regionally uniform unit of interbedded coarse fluvial sandstone and overbank siltstone with SSE directed paleoflow, appears to have been deposited during limited vertical motion on the PCF from ~1.5-1.2 Ma. We find that the base of the Upper Palm Spring Formation (~1.2 Ma) records the inversion of the PCF to a SW-side up oblique strike-slip fault based on the following: the contact between the Lower and Upper Palm Spring Formation is an angular unconformity throughout the Mecca Hills; large (km's) and small (10's m) scale syntectonic (growth) strata within the Upper Palm Spring; clasts of Lower Palm Spring reworked into the Upper Palm Spring Fm; and pronounced contrast between facies of the Upper Palm

  10. Lithology, fault displacement, and origin of secondary calcium carbonate and opaline silica at Trenches 14 and 14D on the Bow Ridge Fault at Exile Hill, Nye County, Nevada

    SciTech Connect

    Taylor, E.M.; Huckins, H.E.

    1995-02-01

    Yucca Mountain, a proposed site for a high-level nuclear-waste repository, is located in southern Nevada, 20 km east of Beatty, and adjacent to the southwest comer of the Nevada Test Site (NTS) (fig. 1). Yucca Mountain is located within the Basin and Range province of the western United States. The climate is semiarid, and the flora is transitional between that of the Mojave Desert to the south and the Great Basin Desert to the north. As part of the evaluation, hydrologic conditions, especially water levels, of Yucca Mountain and vicinity during the Quaternary, and especially the past 20,000 years, are being characterized. In 1982, the US Geological Survey, in cooperation with the US Department of Energy (under interagency agreement DE-A104-78ET44802), excavated twenty-six bulldozer and backhoe trenches in the Yucca Mountain region to evaluate the nature and frequency of Quaternary faulting (Swadley and others, 1984). The trenches were oriented perpendicular to traces of suspected Quaternary faults and across projections of known bedrock faults into Quaternary deposits. Trench 14 exposes the Bow Ridge Fault on the west side of Exile Hill. Although the original purpose of the excavation of trench 14 was to evaluate the nature and frequency of Quaternary faulting on the Bow Ridge Fault, concern arose as to whether or not the nearly vertical calcium carbonate (the term ``carbonate`` in this study refers to calcium carbonate) and opaline silica veins in the fault zone were deposited by ascending waters (ground water). These veins resemble in gross morphology veins commonly formed by hydrothermal processes.

  11. Patterns of faulting and seismicity in the mid-ocean ridge environment

    NASA Astrophysics Data System (ADS)

    Bohnenstiehl, Delwayne Roger

    Abyssal hill faults within the slow-spreading (˜20 mm/yr) mid-ocean ridge environment exhibit displacement-length ratios that are systematically larger than those observed within the fast-spreading environment (˜100 mm/yr). This can be explained by considering the importance of fault linkage in the lateral growth of abyssal hill faults and the limits imposed on maximum fault displacement by the lithospheric thickness within each setting. Within the superfast spreading environment (>140 mm/yr) of the southern East Pacific Rise (EPR), a pattern of inward-dipping master faults is observed, with smaller outward-dipping faults clustered within their hanging walls. This pattern is distinct from the more classic horst and graben morphology described on the fast-spreading northern EPR. The pattern documented on the southern EPR suggests inward-dipping master faults are more sharply curved or listric relative to their abyssal hill equivalents at fast-spreading rates. Boundary element modeling is used to examine the role of axial magma chamber inflation in generating the pattern of faulting observed along the southern EPR. An earthquake catalog derived from the detection of seismically generated T-waves is used to study the decay rate and spatial distribution of mid-ocean ridge aftershock sequences. Generally, aftershock sequences in the mid-ocean ridge setting can be well described by a modified Omori law. Decay constants (p-values) are slightly higher than those previously estimated from stacked sequences derived from the teleseismic record. Three transform fault sequences and one microplate thrust sequence exhibit p-values consistent with the global median value. There is some evidence for higher p-values associated with normal faulting mainshocks along the spreading centers. Although the June 1999 Endeavour segment sequence has been suggested previously to be of tectonic origin, the timing and distribution of earthquakes are inconsistent with the aftershock process

  12. High resolution study of the spatial distributions of abyssal fishes by autonomous underwater vehicle

    NASA Astrophysics Data System (ADS)

    Milligan, R. J.; Morris, K. J.; Bett, B. J.; Durden, J. M.; Jones, D. O. B.; Robert, K.; Ruhl, H. A.; Bailey, D. M.

    2016-05-01

    On abyssal plains, demersal fish are believed to play an important role in transferring energy across the seafloor and between the pelagic and benthic realms. However, little is known about their spatial distributions, making it difficult to quantify their ecological significance. To address this, we employed an autonomous underwater vehicle to conduct an exceptionally large photographic survey of fish distributions on the Porcupine Abyssal Plain (NE Atlantic, 4850 m water depth) encompassing two spatial scales (1–10 km2) on and adjacent to a small abyssal hill (240 m elevation). The spatial distributions of the total fish fauna and that of the two dominant morphotypes (Coryphaenoides sp. 1 and C. profundicolus) appeared to be random, a result contrary to common expectation but consistent with previous predictions for these fishes. We estimated total fish density on the abyssal plain to be 723 individuals km‑2 (95% CI: 601–844). This estimate is higher, and likely more precise, than prior estimates from trawl catch and baited camera techniques (152 and 188 individuals km‑2 respectively). We detected no significant difference in fish density between abyssal hill and plain, nor did we detect any evidence for the existence of fish aggregations at any spatial scale assessed.

  13. High resolution study of the spatial distributions of abyssal fishes by autonomous underwater vehicle

    PubMed Central

    Milligan, R. J.; Morris, K. J.; Bett, B. J.; Durden, J. M.; Jones, D. O. B.; Robert, K.; Ruhl, H. A.; Bailey, D. M.

    2016-01-01

    On abyssal plains, demersal fish are believed to play an important role in transferring energy across the seafloor and between the pelagic and benthic realms. However, little is known about their spatial distributions, making it difficult to quantify their ecological significance. To address this, we employed an autonomous underwater vehicle to conduct an exceptionally large photographic survey of fish distributions on the Porcupine Abyssal Plain (NE Atlantic, 4850 m water depth) encompassing two spatial scales (1–10 km2) on and adjacent to a small abyssal hill (240 m elevation). The spatial distributions of the total fish fauna and that of the two dominant morphotypes (Coryphaenoides sp. 1 and C. profundicolus) appeared to be random, a result contrary to common expectation but consistent with previous predictions for these fishes. We estimated total fish density on the abyssal plain to be 723 individuals km−2 (95% CI: 601–844). This estimate is higher, and likely more precise, than prior estimates from trawl catch and baited camera techniques (152 and 188 individuals km−2 respectively). We detected no significant difference in fish density between abyssal hill and plain, nor did we detect any evidence for the existence of fish aggregations at any spatial scale assessed. PMID:27180728

  14. High resolution study of the spatial distributions of abyssal fishes by autonomous underwater vehicle.

    PubMed

    Milligan, R J; Morris, K J; Bett, B J; Durden, J M; Jones, D O B; Robert, K; Ruhl, H A; Bailey, D M

    2016-01-01

    On abyssal plains, demersal fish are believed to play an important role in transferring energy across the seafloor and between the pelagic and benthic realms. However, little is known about their spatial distributions, making it difficult to quantify their ecological significance. To address this, we employed an autonomous underwater vehicle to conduct an exceptionally large photographic survey of fish distributions on the Porcupine Abyssal Plain (NE Atlantic, 4850 m water depth) encompassing two spatial scales (1-10 km(2)) on and adjacent to a small abyssal hill (240 m elevation). The spatial distributions of the total fish fauna and that of the two dominant morphotypes (Coryphaenoides sp. 1 and C. profundicolus) appeared to be random, a result contrary to common expectation but consistent with previous predictions for these fishes. We estimated total fish density on the abyssal plain to be 723 individuals km(-2) (95% CI: 601-844). This estimate is higher, and likely more precise, than prior estimates from trawl catch and baited camera techniques (152 and 188 individuals km(-2) respectively). We detected no significant difference in fish density between abyssal hill and plain, nor did we detect any evidence for the existence of fish aggregations at any spatial scale assessed. PMID:27180728

  15. Stratigraphic Record of Vertical Crustal Motions in the Past 2-3 Ma Along the Southern San Andreas Fault, Mecca Hills, California

    NASA Astrophysics Data System (ADS)

    McNabb, J. C.; Dorsey, R. J.

    2012-12-01

    Sedimentary rocks exposed on the NE margin of Coachella Valley in the Mecca Hills, southern California, record vertical crustal motions along the San Andreas and associated strike-slip faults. A complex history of subsidence, transport, deposition, and uplift can be interpreted from mapping and measuring of sedimentary rocks, analysis of sedimentary lithofacies, and determination of transport directions from clast imbrications and cross-bedding. The 330 m-thick Mecca Fm rests non-conformably on Pre-Cambrian and Cretaceous crystalline rocks SW of the Painted Canyon Fault (PCF), and is not present NE of the PCF. The Mecca Fm is likely late Pliocene or early Pleistocene in age (Boley et al., 1994), and consists of red boulder conglomerate with imbricated clasts showing SSE to WSW paleoflow. It fines up into pebbly sandstone and is gradationally overlain by the lower member of the Palm Spring Formation (PSF). The PSF is likely younger than 2.0-2.6 Ma based on paleomagnetic studies (Boley et al., 1994) and older than the 0.74-Ma Thermal Canyon Ash high in the section (Rymer, 1989). The lower PSF is 340 m thick, with overall SE paleoflow and 3 lithofacies: (1) laterally extensive fluvial sandstone and siltstone; (2) plutonic-clast conglomerate; and (3) a thin lacustrine limestone unit that correlates across the PCF. The contact between the lower and upper members of the PSF changes from a conformable contact in a small area of the central Mecca Hills to an angular unconformity over a much larger area. The upper PSF is ~650 m thick (similar thickness across the PCF), displays overall transport to the SSE (with local exceptions), and has at least 7 lithofacies: (1) alluvial-fan pebbly sandstone and conglomerate; (2) fluvial sandstone and siltstone; (3) fluvial sandstone with conspicuous arkosic composition; (4) marginal-lacustrine bedded siltstone and sandstone; (5) eolian dune sandstone (6) lacustrine laminated siltstone and mudstone; and (7) local red conglomerate. The

  16. Style and magnitude of Mesozoic thrust faulting in the hinterland of the Sevier thrust belt Pequop Mountains-Wood Hills-East Humboldt Range region, northeast Nevada

    SciTech Connect

    Camilleri, P.A. . Dept. of Geology and Geophysics)

    1993-04-01

    The Pequop Mountains (PM), Wood Hills (WH) and East Humboldt Range (EHR), NE Nevada, provide evidence that the hinterland of the Sevier thrust belt experienced large-magnitude Mesozoic shortening ([>=]55 km) and crustal thickening ([>=] 30 km). These ranges expose a structurally continuous crustal cross section of unmetamorphosed to high pressure upper amphibolite facies Triassic to Precambrian miogeoclinal strata. This sequence lies structurally beneath unmetamorphosed extensional klippen that omit metamorphic grade and crustal section, but also repeat stratigraphic units. Because they repeat stratigraphic units, the underlying miogeoclinal section, or footwall, must have once lain beneath a thrust fault (herein named the Windermere thrust). The footwall of the Windermere thrust was exhumed by two generations of top-to-the-W-NW low-angle normal faults that are distinguished by whether they are depositionally overlapped by Eocene volcanic rocks or if they cut the volcanic rocks in their hanging walls. The latter phase is associated with development of the mid-Tertiary extensional mylonitic shear zone in the EHR. An integration of geobarometric, metamorphic, and map data suggest (1) a NW dip of the footwall of the Windermere thrust with metamorphic facies belts trending perpendicular to dip direction and metamorphic grade increasing down dip, and (2) a top-to-the-SE sense-of-slip for the Windermere thrust. Assuming that the Windermere thrust comprised a flat on the youngest rocks exposed in the footwall (Triassic), the Mesozoic depth to the Windermere thrust in the northern PM is [>=] 7 km, in WH is [approximately]10--16 km, and in the EHR[>=]30 km. The Windermere thrust accommodated a minimum of 50 km of shortening associated with the Independence thrust is [>=] 5 km. These data indicate that the amount of hinterland shortening in NE Nevada greatly exceeds that to the south in the Eureka belt.

  17. Earthquake-by-earthquake fold growth above the Puente Hills blind thrust fault, Los Angeles, California: Implications for fold kinematics and seismic hazard

    USGS Publications Warehouse

    Leon, L.A.; Christofferson, S.A.; Dolan, J.F.; Shaw, J.H.; Pratt, T.L.

    2007-01-01

    Boreholes and high-resolution seismic reflection data collected across the forelimb growth triangle above the central segment of the Puente Hills thrust fault (PHT) beneath Los Angeles, California, provide a detailed record of incremental fold growth during large earthquakes on this major blind thrust fault. These data document fold growth within a discrete kink band that narrows upward from ???460 m at the base of the Quaternary section (200-250 m depth) to 82% at 250 m depth) folding and uplift occur within discrete kink bands, thereby enabling us to develop a paleoseismic history of the underlying blind thrust fault. The borehole data reveal that the youngest part of the growth triangle in the uppermost 20 m comprises three stratigraphically discrete growth intervals marked by southward thickening sedimentary strata that are separated by intervals in which sediments do not change thickness across the site. We interpret the intervals of growth as occurring after the formation of now-buried paleofold scarps during three large PHT earthquakes in the past 8 kyr. The intervening intervals of no growth record periods of structural quiescence and deposition at the regional, near-horizontal stream gradient at the study site. Minimum uplift in each of the scarp-forming events, which occurred at 0.2-2.2 ka (event Y), 3.0-6.3 ka (event X), and 6.6-8.1 ka (event W), ranged from ???1.1 to ???1.6 m, indicating minimum thrust displacements of ???2.5 to 4.5 m. Such large displacements are consistent with the occurrence of large-magnitude earthquakes (Mw > 7). Cumulative, minimum uplift in the past three events was 3.3 to 4.7 m, suggesting cumulative thrust displacement of ???7 to 10.5 m. These values yield a minimum Holocene slip rate for the PHT of ???0.9 to 1.6 mm/yr. The borehole and seismic reflection data demonstrate that dip within the kink band is acquired incrementally, such that older strata that have been deformed by more earthquakes dip more steeply than younger

  18. Temperatures and cooling rates recorded in REE in coexisting pyroxenes in ophiolitic and abyssal peridotites

    NASA Astrophysics Data System (ADS)

    Dygert, Nick; Liang, Yan

    2015-06-01

    Mantle peridotites from ophiolites are commonly interpreted as having mid-ocean ridge (MOR) or supra-subduction zone (SSZ) affinity. Recently, an REE-in-two-pyroxene thermometer was developed (Liang et al., 2013) that has higher closure temperatures (designated as TREE) than major element based two-pyroxene thermometers for mafic and ultramafic rocks that experienced cooling. The REE-in-two-pyroxene thermometer has the potential to extract meaningful cooling rates from ophiolitic peridotites and thus shed new light on the thermal history of the different tectonic regimes. We calculated TREE for available literature data from abyssal peridotites, subcontinental (SC) peridotites, and ophiolites around the world (Alps, Coast Range, Corsica, New Caledonia, Oman, Othris, Puerto Rico, Russia, and Turkey), and augmented the data with new measurements for peridotites from the Trinity and Josephine ophiolites and the Mariana trench. TREE are compared to major element based thermometers, including the two-pyroxene thermometer of Brey and Köhler (1990) (TBKN). Samples with SC affinity have TREE and TBKN in good agreement. Samples with MOR and SSZ affinity have near-solidus TREE but TBKN hundreds of degrees lower. Closure temperatures for REE and Fe-Mg in pyroxenes were calculated to compare cooling rates among abyssal peridotites, MOR ophiolites, and SSZ ophiolites. Abyssal peridotites appear to cool more rapidly than peridotites from most ophiolites. On average, SSZ ophiolites have lower closure temperatures than abyssal peridotites and many ophiolites with MOR affinity. We propose that these lower temperatures can be attributed to the residence time in the cooling oceanic lithosphere prior to obduction. MOR ophiolites define a continuum spanning cooling rates from SSZ ophiolites to abyssal peridotites. Consistent high closure temperatures for abyssal peridotites and the Oman and Corsica ophiolites suggests hydrothermal circulation and/or rapid cooling events (e.g., normal

  19. Mechanism for Normal Faulting in the Subducting Plate at the Mariana Trench

    NASA Astrophysics Data System (ADS)

    Zhou, Z.; Lin, J.; Behn, M. D.; Olive, J. A. L.

    2014-12-01

    We investigate the characteristics of normal faulting between the trench and outer rise in the subducting Pacific plate through analysis of high-resolution multi-beam bathymetry and geophysical data and geodynamic modeling. Analysis of multi-beam bathymetry data reveals significant variations in normal faulting characteristics along the Mariana trench: (1) The vast majority of the observed surface normal faulting scarps are observed to be sub-parallel to the local strike of the Mariana trench axis, indicating that the orientation of normal faults is predominantly controlled by subduction-related stresses rather than by pre-existing abyssal hill fabrics. (2) Trench-parallel normal fault scarps become apparant as the subducting plate approaches the outer rise of the Mariana trench, indicating that normal faulting initiates in this region. (3) Along the Mariana trench, the Challenger Deep region is associated with the greatest trench depth and largest average values of normal fault throw, while regions with seamounts near the trench axis show the smallest average values of fault throw. To explore the mechanisms that control normal faulting in a subducting plate, we perform numerical simulations of elasto-plastic plate subjected to tectonic loading, bending, and horizontal forces from slab pull. Modeling results suggest that bending-induced extensional stresses in the upper plate reaches maximum values near the outer rise, consistent with the onset of normal faulting in this region. However, bending alone does not predict the continued growth of normal faults toward the trench. We hypothesize that this additional fault growth could be related to (1) tectonic stresses induced by steep topographic slopes; and/or (2) slab pulling forces that are originated in the upper mantle due to the negative buoyancy of a subducted slab but are transmitted to the shallower part of the lithospheric plate prior to its subduction.

  20. Tectonic evolution of the Perth Abyssal Plain's Quiet Zone, Southeast Indian Ocean

    NASA Astrophysics Data System (ADS)

    Ehrlich, Zohar Louis; Granot, Roi; Williams, Simon E.

    2013-04-01

    During the Late Jurassic period, the Greater-Indian plate was torn away from Australia, dissociating East Gondwanaland. The Perth Abyssal Plain (PAP) is the southernmost rift segment along the western Australian margin, and has an onset age of ~136 Ma. New marine magnetic and swath bathymetry data, crossing the entire PAP, were acquired recently on geophysical cruise ss2011v06 aboard the R/V Southern Surveyor. These have lead to the outline of conjugate Indian and Australian M-series isochrons in the east and west PAP, respectively [1]. Yet, most of the PAP was created during the Cretaceous Normal Superchron (CNS, 121-83 Ma), a period of no geomagnetic field reversals, hence no comprehensive tectonic model for the PAP exists . Here we present preliminary findings of an analytic bathymetric and magnetic investigation aimed at elucidating the PAP's quiet zone. Recent discoveries regarding the evolution of the geomagnetic field during the CNS [2] provide new time markers that can be utilized to date the oceanic crust. The magnetic anomaly data exhibit the Q2 anomaly marker (~108 Ma), further constraining the spreading history of the PAP. Together with the ridgelet transform method [3] for automated abyssal hill delineation, we present new constraints on the development of crustal construction processes (spreading location, direction and rates) that took place along the PAP spreading center. References: [1] S.E. Williams, J.M. Whittaker, R. Granot, R.D. Muller (in preparation), New constraints on the seafloor spreading history in the Perth Abyssal Plain. [2] Granot, R., J. Dyment, and Y. Gallet (2012), Geomagnetic field variability during the Cretaceous Normal Superchron, Nature Geoscience, 5(3), 220-223. [3] Downey, N. J. and R. W. Clayton (2007), A ridgelet transform method for constraining tectonic models via abyssal-hill morphology, Geochemistry Geophysics Geosystems, 8, Q03004, doi: 10.1029/2006GC001440.

  1. Cost assessment for abyssal seafloor waste isolation

    NASA Astrophysics Data System (ADS)

    Jin, Di; Kite-Powell, Hauke L.

    1998-05-01

    We develop an integrated model for estimating the internal cost of abyssal seafloor waste isolation. The model captures the major economic, engineering, geographic and social factors that influence the management cost for sewage sludge and municipal incinerator ash. Considering five representative metropolitan areas and five proposed abyssal study sites, we apply this model to produce cost estimates for four deep-ocean waste delivery system concepts. The results show that the unit cost depends primarily on regional waste volume, the marine delivery system and transportation distance. Based on available data, the abyssal ocean option may be competitive with present land-based disposal costs in New York City. The option is less competitive in other metropolitan areas.

  2. Global variations in abyssal peridotite compositions

    NASA Astrophysics Data System (ADS)

    Warren, Jessica M.

    2016-04-01

    Abyssal peridotites are ultramafic rocks collected from mid-ocean ridges that are the residues of adiabatic decompression melting. Their compositions provide information on the degree of melting and melt-rock interaction involved in the formation of oceanic lithosphere, as well as providing constraints on pre-existing mantle heterogeneities. This review presents a compilation of abyssal peridotite geochemical data (modes, mineral major elements, and clinopyroxene trace elements) for > 1200 samples from 53 localities on 6 major ridge systems. On the basis of composition and petrography, peridotites are classified into one of five lithological groups: (1) residual peridotite, (2) dunite, (3) gabbro-veined and/or plagioclase-bearing peridotite, (4) pyroxenite-veined peridotite, and (5) other types of melt-added peridotite. Almost a third of abyssal peridotites are veined, indicating that the oceanic lithospheric mantle is more fertile, on average, than estimates based on residual peridotites alone imply. All veins appear to have formed recently during melt transport beneath the ridge, though some pyroxenites may be derived from melting of recycled oceanic crust. A limited number of samples are available at intermediate and fast spreading rates, with samples from the East Pacific Rise indicating high degrees of melting. At slow and ultra-slow spreading rates, residual abyssal peridotites define a large (0-15% modal clinopyroxene and spinel Cr# = 0.1-0.6) compositional range. These variations do not match the prediction for how degree of melting should vary as a function of spreading rate. Instead, the compositional ranges of residual peridotites are derived from a combination of melting, melt-rock interaction and pre-existing compositional variability, where melt-rock interaction is used here as a general term to refer to the wide range of processes that can occur during melt transport in the mantle. Globally, ~ 10% of abyssal peridotites are refractory (0

  3. Timing of detachment faulting in the Bullfrog Hills and Bare Mountain area, southwest Nevada: Inferences from40Ar/39Ar, K-Ar, U-Pb, and fission track thermochronology

    USGS Publications Warehouse

    Hoisch, T.D.; Heizler, M.T.; Zartman, R.E.

    1997-01-01

    Crustal extension in the Bullfrog Hills and Bare Mountain area of southwest Nevada is associated with movement along a regional detachment fault. Normal faulting in the upper plate and rapid cooling (denudation) of the lower plate were coeval with Miocene silicic volcanism and with west-northwest transport along the detachment fault. A west-northwest progression of tilting along upper plate normal faults is indicated by ages of the volcanic rocks in relation to angular unconformities. Near the breakaway, tilting in the upper plate occurred between 12.7 and 11.6 Ma, continued less strongly past 10.7 Ma, and was over by 8.2 Ma. Ten to 20 km west of the breakaway, tilting occurred between 10.7 and 10.33 Ma, continued less strongly after 10.33 Ma, and was over by 8.1 Ma. The cooling histories of the lower plate metamorphic rocks were determined by thermochronologic dating methods: K-Ar and 40Ar/39Ar on muscovite, biotite, and hornblende, 40Ar/39Ar on K-feldspar, U-Pb on apatite, zircon, and sphene, and fission track on apatite, zircon, and sphene. Lower plate rocks 10 km west of the breakaway cooled slowly from Early Cretaceous lower-amphibolite facies conditions through 350??50?? to 300??50??C between 57 and 38 Ma, then cooled rapidly from 205??50?? to 120??50??C between 12.6??1.6 and 11.1??1.9 Ma. Lower plate rocks 20 km west of the breakaway cooled slowly from Early Cretaceous upper-amphibolite facies conditions through 500??50??C at 78-67 Ma, passed through 350??50?? to 300??50??C between 16.3??0.4 and 10.5??0.3 Ma, then cooled rapidly from 285??50?? to 120??50??C between 10.2 and 8.6 Ma. Upper plate tilting and rapid cooling (denudation) of the lower plate occurred simultaneously in the respective areas. The early slow-cooling part of the lower plate thermal histories was probably related to erosion at the Earth's surface, which stripped off about 9 km of material in 50 to 100 m.y. The results indicate an initial fault dip ???30?? and a 12 mm yr-1 west

  4. Bathymetry (Part I), sedimentary regimes (Part II), and abyssal waste-disposal potential near the conterminous United States

    NASA Astrophysics Data System (ADS)

    Bowles, Frederick A.; Vogt, Peter R.; Jung, Woo-Yeol

    1998-05-01

    Placing waste on the seafloor, with the intention that it remain in place and isolated from mankind, requires a knowledge of the environmental factors that may be applicable to a specific seafloor area. DBDB5 (Digital Bathymetric Database gridded at 5' latitude by 5' longitude cell dimension) is used here for regional assessments of seafloor depth, slope, and relief at five surrogate abyssal waste sites; two each in the western Atlantic and eastern Pacific, and one in the Gulf of Mexico. Only Pacific-1 exhibits a `high' slope (2°) by DBDB5 standards, whereas the remaining sites are located on almost level seafloor. Detailed examination of the sites using multibeam-based contour sheets show the area around Atlantic-1 to be a featureless plain. Atlantic-2 and both Pacific sites are surrounded by abyssal hill topography, with local slopes ranging from greater than 6° at all sites to above 15° at Pacific-2. Neither Pacific site features a seafloor as `flat' as at Atlantic-1 or at the Gulf of Mexico site. Locating waste sites on sedimented slopes could have serious consequences due to catastrophic slope failure and downslope displacement of waste by mass sediment-transport processes. Neither slumping nor sliding are perceived as critical processes affecting the surrogate sites because of their locations on negligibly sloping seafloors. However, debris flows and turbidity currents are capable of transporting large volumes of sediment for long distances over low gradients and, in the case of turbidity currents, at great speed. Dispersal of loose waste material by these processes is virtually assured, but less likely if the waste is bagged. The turbidity current problem is alleviated (but not eliminated) by locating waste sites on distal portions of abyssal plains. Both Pacific sites are surrounded by abyssal hills and, in the case of Pacific-2, far beyond the reach of land-derived turbidity currents. Thin sediment cover and low rates of sedimentation have also resulted

  5. A study on the baroclinic structure of the abyssal circulation

    NASA Astrophysics Data System (ADS)

    Luo, De-Hai; Huang, Fei

    2001-03-01

    In this paper, the linear continuously tratified model of the abyssal circulation proposed by Pedlosky (1992) was extended to include the second order term -(γθ zzz ) in the vertical turbulent mixing parameterization of - overline {(w' θ ' )} _z = k_u θ _{zz} - γ θ _{zzz} , in which k v is a vertical diffusion coefficient, and γ is the second order coefficient of turbulent mixing (or simply called γ-term and γ<0 is only allowed). The influence of the γ-term on the baroclinic structure of the abyssal circulation driven by upwelling out of the abyss was investigated. It was found that the γ-term has a noticeable influence on the baroclinic structure of the upwelling driven abyssal circulation. For uniform upwelling, it favors the baroclinic layering of the abyssal circulation in the eastern part of the basin, but prevents the layering in the west. In addition, this parameter was found to decrease the vertically averaging meridional velocity of the abyssal circulation from the west to the east on the southern boundary. For upwelling localized near the eastern boundary, the γ-term favors baroclinic layering of the abyssal circulation in the whole basin. Especially, on the southern boundary the γ-term could strengthen the vertically averaging meridional velocity in the west, but greatly weaken it in the east. The model presented here might be considered as an extension of the Pedlosky baroclinic model of the abyssal circulation.

  6. Biogeochemical, Isotopic and Bacterial Distributions Trace Oceanic Abyssal Circulation.

    PubMed

    Rubino, Angelo; Bensi, Manuel; Hainbucher, Dagmar; Zanchettin, Davide; Mapelli, Francesca; Ogrinc, Nives; Marchetto, Davide; Borin, Sara; Cardin, Vanessa; Fajon, Vesna; Horvat, Milena; Taricco, Carla; Baldi, Franco

    2016-01-01

    We explore the possibility of tracing routes of dense waters toward and within the ocean abyss by the use of an extended set of observed physical and biochemical parameters. To this purpose, we employ mercury, isotopic oxygen, biopolymeric carbon and its constituents, together with indicators of microbial activity and bacterial diversity found in bottom waters of the Eastern Mediterranean. In this basin, which has been considered as a miniature global ocean, two competing sources of bottom water (one in the Adriatic and one in the Aegean seas) contribute to the ventilation of the local abyss. However, due to a recent substantial reduction of the differences in the physical characteristics of these two water masses it has become increasingly complex a water classification using the traditional approach with temperature, salinity and dissolved oxygen alone. Here, we show that an extended set of observed physical and biochemical parameters allows recognizing the existence of two different abyssal routes from the Adriatic source and one abyssal route from the Aegean source despite temperature and salinity of such two competing sources of abyssal water being virtually indistinguishable. Moreover, as the near-bottom development of exogenous bacterial communities transported by convectively-generated water masses in the abyss can provide a persistent trace of episodic events, intermittent flows like those generating abyssal waters in the Eastern Mediterranean basin may become detectable beyond the availability of concomitant measurements. PMID:26761666

  7. Biogeochemical, Isotopic and Bacterial Distributions Trace Oceanic Abyssal Circulation

    PubMed Central

    Rubino, Angelo; Bensi, Manuel; Hainbucher, Dagmar; Zanchettin, Davide; Mapelli, Francesca; Ogrinc, Nives; Marchetto, Davide; Borin, Sara; Cardin, Vanessa; Fajon, Vesna; Horvat, Milena; Taricco, Carla; Baldi, Franco

    2016-01-01

    We explore the possibility of tracing routes of dense waters toward and within the ocean abyss by the use of an extended set of observed physical and biochemical parameters. To this purpose, we employ mercury, isotopic oxygen, biopolymeric carbon and its constituents, together with indicators of microbial activity and bacterial diversity found in bottom waters of the Eastern Mediterranean. In this basin, which has been considered as a miniature global ocean, two competing sources of bottom water (one in the Adriatic and one in the Aegean seas) contribute to the ventilation of the local abyss. However, due to a recent substantial reduction of the differences in the physical characteristics of these two water masses it has become increasingly complex a water classification using the traditional approach with temperature, salinity and dissolved oxygen alone. Here, we show that an extended set of observed physical and biochemical parameters allows recognizing the existence of two different abyssal routes from the Adriatic source and one abyssal route from the Aegean source despite temperature and salinity of such two competing sources of abyssal water being virtually indistinguishable. Moreover, as the near-bottom development of exogenous bacterial communities transported by convectively-generated water masses in the abyss can provide a persistent trace of episodic events, intermittent flows like those generating abyssal waters in the Eastern Mediterranean basin may become detectable beyond the availability of concomitant measurements. PMID:26761666

  8. Eurasian Arctic abyssal waters are warming

    NASA Astrophysics Data System (ADS)

    Schauer, Ursula; von Appen, Wilken-Jon; Somavilla Cabrillo, Raquel; Behrendt, Axel; Rabe, Benjamin

    2016-04-01

    In the past decades, not only the upper water layers, but also the deepest layers of the Arctic Ocean have been warming. Observations show that the rate of warming varies markedly in the different basins with the fastest warming in the deep Greenland Sea (ca. 0.11°C per decade) and the Eurasian Basin featuring an average rate of ca. 0.01°C per decade. While the warming in the Greenland Sea is attributed to ongoing export of relatively warmer deep waters from the Arctic Ocean in combination with the halt of deep convection, the reason of Eurasian Basin deep warming is less clear. We discuss possible causes such as changes in the abyssal ventilation through slope convection, advection from other basins and/or geothermal heating through various sources.

  9. Abyssal undular vortices in the Eastern Mediterranean basin.

    PubMed

    Rubino, A; Falcini, F; Zanchettin, D; Bouche, V; Salusti, E; Bensi, M; Riccobene, G; De Bonis, G; Masullo, R; Simeone, F; Piattelli, P; Sapienza, P; Russo, S; Platania, G; Sedita, M; Reina, P; Avolio, R; Randazzo, N; Hainbucher, D; Capone, A

    2012-01-01

    Abyssal temperature and velocity observations performed within the framework of the Neutrino Mediterranean Observatory, a project devoted to constructing a km(3)-scale underwater telescope for the detection of high-energy cosmic neutrinos, demonstrate cross-fertilization between subnuclear physics and experimental oceanography. Here we use data collected south of Sicily in the Ionian abyssal plain of the Eastern Mediterranean (EM) basin to show for the first time that abyssal vortices exist in the EM, at depths exceeding 2,500 m. The eddies consist of chains of near-inertially pulsating mesoscale cyclones/anticyclones. They are embedded in an abyssal current flowing towards North-Northwest. The paucity of existing data does not allow for an unambiguous determination of the vortex origin. A local generation mechanism seems probable, but a remote genesis cannot be excluded a priori. The presence of such eddies adds further complexity to the discussion of structure and evolution of water masses in the EM. PMID:22588296

  10. STUDY OF ABYSSAL SEAFLOOR ISOLATION OF CONTAMINATED SEDIMENTS CONCLUDED

    EPA Science Inventory

    Recognizing the rapidly decreasing availability of disposal sites on land, in 1993 Congress directed the Department of Defense to assess the technical and scientific feasibility of isolating contaminated dredged material on the abyssal seafloor. The Naval Research Laboratory (NRL...

  11. Sawtooth segmentation and deformation processes on the southern San Andreas fault, California

    NASA Technical Reports Server (NTRS)

    Bilham, R.; Williams, P.

    1985-01-01

    Five contiguous 12-13 km fault segments form a sawtooth geometry on the southernmost San Andreas fault. The kinematic and morphologic properties of each segment depend on fault strike, despite differences of strike between segments of as little as 3 degrees. Oblique slip (transpression) of fault segments within the Indio Hills, Mecca Hills and Durmid Hill results from an inferred 8:1 ratio of dextral slip to convergence across the fault zone. Triggered slip and creep are confined almost entirely to transpressive segments of the fault. Durmid Hill has been formed in the last 28 + or - 6 ka by uplift at an average rate of 3 + or - 1 mm/a.

  12. Abyssal benthos of the central Indian Ocean

    NASA Astrophysics Data System (ADS)

    Parulekar, A. H.; Harkantra, S. N.; Ansari, Z. A.; Matondkar, S. G. P.

    1982-12-01

    Quantitative studies of the abyssal benthos (3600 to 5300 m) of the central Indian Ocean show a rich fauna and high standing crops. Density of 3 meiofaunal and 12 macrofaunal taxa are large (2175 to 15233; x = 6441 m -2) Polychaetes (41.6%), peracarid crustaceans (31.7%), ophiuroids (12.2%), echiuroid-bryozoa (9.7%), molluscs (4.8%), and agglutinating rhizopod protozoans form the macrofauna. Meiofaunal taxa are nematodes (69.4%), harpacticoid copepods (26.6%), and ostracods (4%). Meiofauna abundances are positively correlated with distance from shore, whereas the distribution and abundance of macrofauna are independent of variations in depth and distance from the shore. Ratio of macro to meiofauna in the total population is 1 to 31. The benthic standing crop is uniformly high (0.54 to 13.73 g m -2; x = 2.70 g m -2) and many times larger than previously reported for comparable depths in other oceans and from the same region. Biomass values are significantly related to distance from shore and the type of substratum. Contribution of macro and meiofauna to the total standing crop was in the ratio of 31 to 1. High benthic biomass and rich fauna are consequences of high organic production in the euphotic zone. The correlation between biomass of the total oxidizable organic matter in the water column and the benthic standing crop is statistically significant ( r = -0.64) at the P < 0.05 level. Rich fauna and high standing crop were associated with the occurrence of polymetallic nodules.

  13. Abyssal circulation in the Somali Basin

    NASA Astrophysics Data System (ADS)

    Dengler, M.; Quadfasel, D.; Schott, F.; Fischer, J.

    The bottom and deep circulation in the Somali Basin are investigated on the basis of hydrographic and direct velocity profiles from three shipboard surveys carried out during the southwest monsoon in 1995 and of velocity time series from the WOCE mooring array ICM7. The inflow of bottom water into the Somali Basin through the Amirante Passage drives a thermohaline circulation, which may be modulated by the monsoon wind forcing. Details of the abyssal circulation have been discussed controversially. Deep velocity records from the mooring array in the northern Somali Basin are dominated by fluctuations with periods of 30-50 days and amplitudes above 5 cm s -1. Despite this strong variability annual record averages indicate the existence of a deep western boundary current (DWBC) below 3000 m at the base of the continental slope south of Socotra Island as part of a cyclonic bottom circulation. The southwestward DWBC transport off Socotra Island is estimated to 2±1.3 Sv. The bottom and deep water exchange between the Somali and Arabian Basin north of 7°N is estimated from two cross-basin geostrophic velocity sections referenced by vertically averaged LADCP currents. For the bottom water, an eastward transport into the Arabian Basin of 1.4±0.5 Sv and 2.1±0.6 Sv was determined in June and August, respectively, while for the deep-water layer above 3500 m eastward transports of 3.6±2.3 Sv in June and 4.0±2.4 Sv in August were obtained.

  14. Internal wave structures in abyssal cataract flows

    NASA Astrophysics Data System (ADS)

    Makarenko, Nikolay; Liapidevskii, Valery; Morozov, Eugene; Tarakanov, Roman

    2014-05-01

    We discuss some theoretical approaches, experimental results and field data concerning wave phenomena in ocean near-bottom stratified flows. Such strong flows of cold water form everywhere in the Atlantic abyssal channels, and these currents play significant role in the global water exchange. Most interesting wave structures arise in a powerful cataract flows near orographic obstacles which disturb gravity currents by forced lee waves, attached hydraulic jumps, mixing layers etc. All these effects were observed by the authors in the Romanche and Chain fracture zones of Atlantic Ocean during recent cruises of the R/V Akademik Ioffe and R/V Akademik Sergei Vavilov (Morozov et al., Dokl. Earth Sci., 2012, 446(2)). In a general way, deep-water cataract flows down the slope are similar to the stratified flows examined in laboratory experiments. Strong mixing in the sill region leads to the splitting of the gravity current into the layers having the fluids with different densities. Another peculiarity is the presence of critical layers in shear flows sustained over the sill. In the case under consideration, this critical level separates the flow of near-bottom cold water from opposite overflow. In accordance with known theoretical models and laboratory measurements, the critical layer can absorb and reflect internal waves generated by the topography, so the upward propagation of these perturbations is blocked from above. High velocity gradients were registered downstream in the vicinity of cataract and it indicates the existence of developed wave structures beyond the sill formed by intense internal waves. This work was supported by RFBR (grants No 12-01-00671-a, 12-08-10001-k and 13-08-10001-k).

  15. Brain areas in abyssal demersal fishes.

    PubMed

    Wagner, H J

    2001-06-01

    Four areas of the brain which receive primary projections from chemical senses ([1] olfactory bulb, [2] gustatory area including facial and vagal lobes), the eye ([3] optic tectum), and mechanosensory, and-hair-cell based systems i.e. the lateral line, vestibular and auditory systems ([4] trigeminal and octavolateral regions) have been studied and relative size differences used to make deductions on the sensory preferences of 35 fish species living on or near the bottom of the deep sea. Furthermore the relative volumes of the telencephalon and the corpus cerebelli were determined. Two evaluation modes were applied: (1) the relative mean of each system was calculated and species with above-average areas identified; (2) a cluster analysis established multivariate correlations among the sensory systems. The diversity of sensory brain areas in this population of fish suggests that the benthic and epibenthic environment of the abyss presents a rich sensory environment. Vision seems to be the single most important sense suggesting the presence of relevant bioluminescent stimuli. However, in combination the chemical senses, smell and taste, surpass the visual system; most prominent among them is olfaction. The trigeminal/octavolateral area indicating the role of lateral line input and possibly audition is also well represented, but only in association with other sensory modalities. A large volume telencephalon was often observed in combination with a prominent olfactory system, whereas cerebella of unusually large sizes occurred in species with above-average visual, hair-cell based, but also olfactory systems, confirming their role as multimodal sensorimotor coordination centers. In several species the predictions derived from the volumetric brain analyses were confirmed by earlier observations of stomach content and data obtained by baited cameras. PMID:11713385

  16. Biogeochemical evidence of vigorous mixing in the abyssal ocean

    NASA Astrophysics Data System (ADS)

    Lampitt, Richard S.; Popova, Ekaterina E.; Tyrrell, Toby

    2003-05-01

    The metabolic activities of biological communities living at the abyssal seabed create a strong source of nutrients and a sink for oxygen. If the published estimates of vertical mixing based on instantaneous microstructure measurements are correct, near to the abyssal seabed away from rough topographic features there should be enhanced concentrations of nitrate and phosphate and depletion of oxygen. Recent data on the vertical concentration profiles of inorganic nutrients and oxygen over the bottom 1000 m of the water column (World Ocean Circulation Experiment - WOCE) provide no such evidence. It is concluded that the effective vertical mixing rates are much more vigorous than previously indicated and may even be higher than estimates of average basin scale rates based on temperature and salinity distributions. We propose that the enhanced mixing associated with rough topography influences the entire volume of the abyssal ocean on short time scales (e.g., one month - one year).

  17. Evidences of intraplate deformation in the West Madeira Abyssal Plain (eastern North Atlantic) from seismic reflection and multibeam swath bathymetry data

    NASA Astrophysics Data System (ADS)

    Roque, C.; Simões, M.; Lourenço, N.; Pinto de Abreu, M.

    2009-04-01

    The West Madeira Abyssal Plain is located in the eastern North Atlantic off Madeira Islands, forming part of the Canary Basin and reaching a mean water depth of 5300 m. This region is also located within Africa plate at about 500 km southwards from the Açores-Gibraltar plate boundary, and for that reason lacks seismic activity. Although this region being located in an intraplate setting, the presence of faulted sediments was reported in several works published during the eighties of last century following a study conducted in late 1970s to evaluate the feasibility of disposal of high-level radioactive wastes in the ocean. According these works, the Madeira Abyssal Plain sediments are cut by many normal growth faults and this deformation is a result of compaction and dewatering of the sediments. Evidences of tectonic deformation of oceanic sediments in intraplate settings are uncommon, but folded sediments and reverse faults extending into the basement, were recognized in the equatorial Indian Ocean and in the West African continental margin. Recently, during 2006 multi-channel seismic reflection and multibeam swath bathymetry surveys were carried out in the West Madeira Abyssal Plain by EMEPC in order to prepare the Portuguese proposal for the extension of the continental shelf. The seismic lines were acquired onboard R/V Akademik Shatskiy using a source of 5720 cu in bolt gun array, cable length of 7950 m and shot interval of 50.00 m. The multibeam swath bathymetry was acquired onboard NRP Gago Coutinho, and allowed a high resolution mapping of the main geomorphological features. The multichannel seismic lines, oriented WNW-ESE, image the Madeira island lower slope located at about 4000 m water depth and the almost flat abyssal plain at about 5300 m water depth. These seismic lines show a thick sedimentary succession that reaches a maximum thickness of about 1.5 sec twt in the deepest parts of the West Madeira Abyssal Plain, overlying an irregular diffractive

  18. Barophilic Bacteria Associated with Digestive Tracts of Abyssal Holothurians

    PubMed Central

    Deming, Jody W.; Colwell, Rita R.

    1982-01-01

    Abyssal holothurians and sediment samples were collected at depths of 4,430 to 4,850 m in the Demerara abyssal plain. Bacterial concentrations in progressive sections of the holothurian digestive tract, as well as in surrounding surface sediments, were determined by epifluorescence microscopy. Total bacterial counts in sediments recently ingested by the animals were 1.5- to 3-fold higher than in surrounding sediments at the deepest station. Lowest counts were observed consistently in the foregut, where the digestive processes of the holothurian are believed to occur. In most animals, counts increased 3- to 10-fold in the hindgut. Microbial activity at 3°C and in situ and atmospheric pressure were determined for gut and sediment samples by measuring the utilization of [14C]glutamic acid, the doubling time of the mixed-population of culturable bacteria, and the percentage of the total bacterial count responsive to yeast extract in the presence of nalidixic acid, using epifluorescence microscopy. A barophilic microbial population, showing elevated activity under deep-sea pressure, was detected by all three methods in sediments removed from the hindgut. Transmission electron micrographs revealed intact bacteria directly associated with the intestinal lining only in the hindgut. The bacteria are believed to be carried as an actively metabolizing, commensal gut flora that transforms organic matter present in abyssal sediments ingested by the holothurian. Using data obtained in this study, it was calculated that sediment containing organic matter altered by microbial activity cleared the holothurian gut every 16 h, suggesting that abyssal holothurians and their associated gut flora are important participants in nutrient cycles of the abyssal benthic ocean. Images PMID:16346137

  19. Engineering concepts for the placement of wastes on the abyssal seafloor

    NASA Astrophysics Data System (ADS)

    Valent, Philip J.; Palowitch, Andrew W.; Young, David K.

    1998-05-01

    The Naval Research Laboratory (NRL), with industry and academic participation, has completed a study of the concept of isolating industrial wastes (i.e., sewage sludge, fly ash from municipal incinerators, and dredged material) on the abyssal seafloor. This paper presents results of the technical and economic assessment of this waste management concept. The results of the environmental impacts portion of the study are presented in a companion paper. The technical assessment began with identification of 128 patents addressing waste disposal in the ocean. From these 128 patents, five methods for transporting wastes through the water column and emplacing wastes within an easily monitored area on the abyssal seafloor were synthesized for technical assessment. In one method waste is lowered to the seafloor in a bucket of 190 m 3. In a second method waste is pumped down to the seafloor in pipes, 1.37 m in diameter and 6100 m in length. In a third method waste is free-fallen from the ocean surface in 380-m 3 geosynthetic fabric containers (GFCs). In the fourth and fifth methods, waste is carried to near the seafloor in GFCs transported in (a) a 20,000 metric ton displacement (loaded), unpowered, unmanned submersible glider, or (b) a 2085 metric ton displacement (loaded) disk-shaped transporter traversing to and from the seafloor much like an untethered elevator. In the last two methods the transporter releases the GFCs to free-fall the last few hundred meters to the seafloor. Two reliability analyses, a Fault Tree Analysis (FTA), and a Failure Modes, Effects, and Criticality Analysis (FMECA), showed that the free-fall GFC method posed the least overall relative risk, provided that fabric container and transporter designs eliminate the potential for tearing of the containers on release from the surface transporter. Of the five methods, the three GFC methods were shown to offer cost-effective waste management options when compared with present-day waste management

  20. Mineral compositions of plutonic rocks from the Lewis Hills massif, Bay of Islands ophiolite

    NASA Technical Reports Server (NTRS)

    Smith, Susan E.; Elthon, Don

    1988-01-01

    Mineral compositions of residual and cumulate rocks from the Lewis Hills massif of the Bay of Islands ophiolite complex are reported and interpreted in the context of magnetic processes involved in the geochemical evolution of spatially associated diabase dikes. The mineral compositions reflect greater degrees of partial melting than most abyssal peridotites do and appear to represent the most depleted end of abyssal peridotite compositions. Subsolidus equilibration between Cr-Al spinal and olivine generally has occurred at temperatures of 700 to 900 C. The spinel variations agree with the overall fractionation of basaltic magmas producing spinels with progressively lower Cr numbers. The compositions of clinopyroxenes suggest that the fractionation of two different magma series produced the various cumulate rocks.

  1. Orphan Strontium-87 in Abyssal Peridotites: Daddy Was a Granite

    NASA Astrophysics Data System (ADS)

    Snow, Jonathan E.; Hart, Stanley R.; Dick, Henry J. B.

    1993-12-01

    The 87Sr/86Sr ratios in some bulk abyssal and alpine peridotites are too high to be binary mixtures of depleted mantle and seawater components. The apparent excess, or "orphan," 87Sr appears to be separated from its radioactive parent. Such observations were widely held to be analytical artifacts. Study of several occurrences of orphan 87Sr shows that the orphan component in abyssal peridotite is located in the alteration products of olivine and enstatite in the peridotite. The orphan 87Sr is most likely introduced by infiltration of low-temperature (<200^circC) seawater bearing suspended detrital particulates. These particulates include grains of detrital clay that are partly derived from continental (that is, granitic) sources and thus are highly radiogenic. Orphan 87Sr and other radiogenic isotopes may provide a tracer for low-temperature seawater penetrating into the oceanic crust.

  2. Orphan strontium-87 in abyssal peridotites: daddy was a granite.

    PubMed

    Snow, J E; Hart, S R; Dick, H J

    1993-12-17

    The (87)Sr/(86)Sr ratios in some bulk abyssal and alpine peridotites are too high to be binary mixtures of depleted mantle and seawater components. The apparent excess, or "orphan," (87)Sr appears to be separated from its radioactive parent. Such observations were widely held to be analytical artifacts. Study of several occurrences of orphan (87)Sr shows that the orphan component in abyssal peridotite is located in the alteration products of olivine and enstatite in the peridotite. The orphan (87)Sr is most likely introduced by infiltration of low-temperature (<200 degrees C) seawater bearing suspended detrital particulates. These particulates include grains of detrital clay that are partly derived from continental (that is, granitic) sources and thus are highly radiogenic. Orphan (87)Sr and other radiogenic isotopes may provide a tracer for low-temperature seawater penetrating into the oceanic crust. PMID:17829634

  3. Study of abyssal seafloor isolation of contaminated sediments concluded

    SciTech Connect

    Valent, P.

    1998-12-31

    Recognizing the rapidly decreasing availability of disposal sites on land, in 1993 Congress directed the Department of Defense to assess the technical and scientific feasibility of isolating contaminated dredged material on the abyssal seafloor. The Naval Research Laboratory (NRL) conducted and managed the assessment, which was funded during its first year by the Strategic Environmental Research and Development Program and in the following two years by the Defense Advanced Research Projects Agency. NRL carried out the projects in collaboration with participants from academic institutions and industrial organizations. The seafloor isolation concept is an attractive management option for contaminated dredged material because, if abyssal isolation is feasible and environmentally sound, air, land, or water supplies would not be contaminated. The participants concluded that it is technically and environmentally feasible. In ports where shipping costs are high, abyssal seafloor isolation is a cost-competitive strategy. They also outlined the architecture of a system to monitor conditions at the site and to detect and measure possible leaks of contaminated material.

  4. Comment on "Glacial cycles drive variations in the production of oceanic crust".

    PubMed

    Goff, John A

    2015-09-01

    Crowley et al. (Reports, 13 March 2015, p. 1237) propose that abyssal hill topography can be generated by variations in volcanism at mid-ocean ridges modulated by Milankovitch cycle-driven changes in sea level. Published values for abyssal hill characteristic widths versus spreading rate do not generally support this hypothesis. I argue that abyssal hills are primarily fault-generated rather than volcanically generated features. PMID:26339022

  5. Comment on “Glacial cycles drive variations in the production of oceanic crust”

    NASA Astrophysics Data System (ADS)

    Goff, John A.

    2015-09-01

    Crowley et al. (Reports, 13 March 2015, p. 1237) propose that abyssal hill topography can be generated by variations in volcanism at mid-ocean ridges modulated by Milankovitch cycle-driven changes in sea level. Published values for abyssal hill characteristic widths versus spreading rate do not generally support this hypothesis. I argue that abyssal hills are primarily fault-generated rather than volcanically generated features.

  6. Can the source–sink hypothesis explain macrofaunal abundance patterns in the abyss? A modelling test

    PubMed Central

    Hardy, Sarah M.; Smith, Craig R.; Thurnherr, Andreas M.

    2015-01-01

    Low food availability is a major structuring force in deep-sea benthic communities, sustaining only very low densities of organisms in parts of the abyss. These low population densities may result in an Allee effect, whereby local reproductive success is inhibited, and populations are maintained by larval dispersal from bathyal slopes. This slope–abyss source–sink (SASS) hypothesis suggests that the abyssal seafloor constitutes a vast sink habitat with macrofaunal populations sustained only by an influx of larval ‘refugees' from source areas on continental slopes, where higher productivity sustains greater population densities. Abyssal macrofaunal population densities would thus be directly related to larval inputs from bathyal source populations. We evaluate three predictions derived from the SASS hypothesis: (i) slope-derived larvae can be passively transported to central abyssal regions within a single larval period, (ii) projected larval export from slopes to the abyss reproduces global patterns of macrofaunal abundance and (iii) macrofaunal abundance decreases with distance from the continental slope. We find that abyssal macrofaunal populations are unlikely to be sustained solely through influx of larvae from slope sources. Rather, local reproduction probably sustains macrofaunal populations in relatively high-productivity abyssal areas, which must also be considered as potential larval source areas for more food-poor abyssal regions. PMID:25948686

  7. Can the source-sink hypothesis explain macrofaunal abundance patterns in the abyss? A modelling test.

    PubMed

    Hardy, Sarah M; Smith, Craig R; Thurnherr, Andreas M

    2015-06-01

    Low food availability is a major structuring force in deep-sea benthic communities, sustaining only very low densities of organisms in parts of the abyss. These low population densities may result in an Allee effect, whereby local reproductive success is inhibited, and populations are maintained by larval dispersal from bathyal slopes. This slope-abyss source-sink (SASS) hypothesis suggests that the abyssal seafloor constitutes a vast sink habitat with macrofaunal populations sustained only by an influx of larval 'refugees' from source areas on continental slopes, where higher productivity sustains greater population densities. Abyssal macrofaunal population densities would thus be directly related to larval inputs from bathyal source populations. We evaluate three predictions derived from the SASS hypothesis: (i) slope-derived larvae can be passively transported to central abyssal regions within a single larval period, (ii) projected larval export from slopes to the abyss reproduces global patterns of macrofaunal abundance and (iii) macrofaunal abundance decreases with distance from the continental slope. We find that abyssal macrofaunal populations are unlikely to be sustained solely through influx of larvae from slope sources. Rather, local reproduction probably sustains macrofaunal populations in relatively high-productivity abyssal areas, which must also be considered as potential larval source areas for more food-poor abyssal regions. PMID:25948686

  8. Geologic map of the Bodie Hills, California and Nevada

    USGS Publications Warehouse

    John, David A.; du Bray, Edward A.; Box, Stephen E.; Vikre, Peter G.; Rytuba, James J.; Fleck, Robert J.; Moring, Barry C.

    2015-01-01

    The Bodie Hills covers about 1,200 km2 straddling the California-Nevada state boundary just north of Mono Lake in the western part of the Basin and Range Province, about 20 km east of the central Sierra Nevada. The area is mostly underlain by the partly overlapping, middle to late Miocene Bodie Hills volcanic field and Pliocene to late Pleistocene Aurora volcanic field (John and others, 2012). Upper Miocene to Pliocene sedimentary deposits, mostly basin-filling sediments, gravel deposits, and fanglomerates, lap onto the west, north, and east sides of the Bodie Hills, where they cover older Miocene volcanic rocks. Quaternary surficial deposits, including extensive colluvial, fluvial, glacial, and lacustrine deposits, locally cover all older rocks. Miocene and younger rocks are tilted ≤30° in variable directions. These rocks are cut by several sets of high-angle faults that exhibit a temporal change from conjugate northeast-striking left-lateral and north-striking right-lateral oblique-slip faults in rocks older than about 9 Ma to north- and northwest-striking dip-slip faults in late Miocene rocks. The youngest faults are north-striking normal and northeast-striking left-lateral oblique-slip faults that cut Pliocene-Pleistocene rocks. Numerous hydrothermal systems were active during Miocene magmatism and formed extensive zones of hydrothermally altered rocks and several large mineral deposits, including gold- and silver-rich veins in the Bodie and Aurora mining districts (Vikre and others, in press).

  9. The Role of Melt Supply in the Formation of Long-Lived Oceanic Detachment Faults

    NASA Astrophysics Data System (ADS)

    Tucholke, B. E.; Behn, M. D.; Buck, W. R.; Qin, R.; Lin, J.

    2006-12-01

    . Fault-slip duration decreases quickly as an increasing fraction of plate separation is taken up by magmatic accretion. With decreasing magma supply, however, long-lived slip persists to very low values of melt input and detachments may form on both sides of a stable keystone block at the spreading axis. Model topography produced by about 40 percent magmatic extension best matches the megamullion and conjugate abyssal-hill structure most commonly observed on mid-ocean ridges. In contrast, models of fully tectonic extension produce a chaotic pattern of relatively short- duration faults (up to a few 100 k.y.) caused by large bending stresses primarily in fault footwalls but also in hanging walls. Our geologic observations and numerical modeling results may provide important constraints on the interpretation of the magnitude of tectonic versus magmatic extension on intermediate- to ultra-slow- spreading ridges.

  10. A Deep Cabled Observatory: Biology and Physics in the Abyss

    NASA Astrophysics Data System (ADS)

    Howe, Bruce M.

    2014-11-01

    The ALOHA Cabled Observatory (ACO) is the deepest operating observatory on the planet, providing power and communications to scientific instruments on the seafloor. In the future, ACO will add water column measurements, from the seafloor to the surface, using moorings and undersea vehicles. Recent results from video monitoring of deep-sea life and from temperature sensors illustrate the benefit of and need for long-term, sustained, continuous sampling in this abyssal context. The observatory is located at Station ALOHA (A Long-Term Oligotrophic Habitat Assessment), 100 kilometers north of Oahu, at 4728-meter water depth (Figure 1, top).

  11. Variations in heat flow across the ocean—continent transition in the Iberia abyssal plain

    NASA Astrophysics Data System (ADS)

    Louden, Keith E.; Sibuet, Jean-Claude; Harmegnies, Francois

    1997-10-01

    New heat flow observations have been made in the Iberia abyssal plain off the Galicia margin along the transect of Ocean Drilling Program Leg 149 drill sites, in order to investigate the nature of this unusually wide and deep continent-ocean transition region. Our results indicate the presence of three separate zones. Average values of 47.5 ± 3 mW m -2 in the westernmost zone III agree with predictions of standard oceanic lithospheric models for its estimated age of 126 Ma. In contrast, the heat flow within zone II is 5-15 mW m -2 higher than predicted, assuming that the mantle heat flow remains constant across the basin. This region of high values is coincident with the location of a major intra-crustal "S"-type reflector east of ODP Site 900, and the anomaly is consistent with the presence of 2-3 km of primarily upper continental crust above the reflector, with concentrations of radiogenic components similar to those from granodiorite samples dredged off Galicia Bank. It is not, however, consistent with the low values of heat production measured on gabbroic samples from its western end at ODP Site 900. In zone I, detailed measurements across the tilted fault block south of ODP Site 901 show consistent variations which closely match predictions due to the effects of basement structure and sediment deposition. There is no evidence for variations due to vertical convective transport along the dipping basement fault block. Once corrected for these variations, measurements in zone 1 yield average values that agree quite well with previous measurements across Galicia Bank, indicating no systematic landward increase in heat flow with decreasing amounts of continental extension.

  12. The West Beverly Hills Lineament and Beverly Hills High School: Ethical Issues in Geo-Hazard Communication

    NASA Astrophysics Data System (ADS)

    Gath, Eldon; Gonzalez, Tania; Roe, Joe; Buchiarelli, Philip; Kenny, Miles

    2014-05-01

    Results of geotechnical studies for the Westside Subway were disclosed in a public hearing on Oct. 19, 2011, showing new "active faults" of the Santa Monica fault and the West Beverly Hills Lineament (WBHL), identified as a northern extension of the Newport-Inglewood fault. Presentations made spoke of the danger posed by these faults, the possibility of killing people, and how it was good news that these faults had been discovered now instead of later. The presentations were live and are now memorialized as YouTube videos, (http://www.youtube.com/watch?v=Omx2BTIpzAk and others). No faults had been physically exposed or observed by the study; the faults were all interpreted from cone penetrometer probes, supplemented by core borings and geophysical transects. Several of the WBHL faults traversed buildings of the Beverly Hills High School (BHHS), triggering the school district to geologically map and characterize these faults for future planning efforts, and to quantify risk to the students in the 1920's high school building. 5 exploratory trenches were excavated within the high school property, 12 cone penetrometers were pushed, and 26-cored borings were drilled. Geologic logging of the trenches and borings and interpretation of the CPT data failed to confirm the presence of the mapped WBHL faults, instead showing an unfaulted, 3° NE dipping sequence of mid-Pleistocene alluvial fan deposits conformably overlying an ~1 Ma marine sand. Using 14C, OSL, and soil pedology for stratigraphic dating, the BHHS site was cleared from fault rupture hazards and the WBHL was shown to be an erosional margin of Benedict Canyon, partially buttressed by 40-200 ka alluvial deposits from Benedict Wash. The consequence of the Westside Subway's active fault maps has been the unexpected expenditure of millions of dollars for emergency fault investigations at BHHS and several other private properties within a densely developed urban highrise environment. None of these studies have found

  13. Direct observation of episodic growth in an abyssal xenophyophore (Protista)

    NASA Astrophysics Data System (ADS)

    Gooday, A. J.; Bett, B. J.; Pratt, D. N.

    1993-11-01

    Three specimens of the xenophyophore Reticulammina labyrinthica were photographed on the Madeira Abyssal Plain (31°6.1'N, 21°10.9'W; 4944 m) using the Bathysnap time-lapse camera system. During the 8 month observation period, the specimens underwent an estimated 3-10 fold increase in volume. Growth occurred episodically in several distinct phases, each lasting 2-3 days, during which sediment was collected and incorporated into the test. These phases were separated by fairly regular periods of about 2 months when the organisms showed little obvious activity. The growth phases were approximately synchronous between specimens. However, it is not clear whether the periodicity and apparent synchronization of these events resulted from an external (environmental) cue or whether growth is internally controlled and the synchronization arose by chance. These unique observations, which represent the first direct measurement of growth in any abyssal organism living outside a hydrothermal vent field, suggest that xenophyophores combine test growth with deposit feeding. The tests appear to grow more quickly, and to be more active, dynamic structures, than previously believed.

  14. Top of the hill.

    PubMed

    Lubell, Jennifer

    2009-08-24

    With healthcare reform the hottest topic in Washington (and at congressional town halls) this summer, it's no surprise President Barack Obama tops our 100 Most Powerful People in Healthcare ranking, joined by plenty of other power players on the Hill. "Clearly, the president is pushing hard on his goals to expand access to care, to reform health insurance and to control costs," says LifePoint's Bill Carpenter. PMID:19731430

  15. Nose Hill Artifacts

    ERIC Educational Resources Information Center

    Hansen, Vivian

    2008-01-01

    A Blackfoot woman, caught in the act of adultery, was condemned at this site to have her nose cut off as a penalty for her actions. People do not know her story. The tribe cast it on the ground. And so She, Nose Hill, was named. John Laurie Boulevard holds her mound in a circlet of asphalt, defining the map of her "terra incognita." She is a park…

  16. 'Columbia Hills' Oblique View

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1: Spirit's Long Journey, Sol 450

    This perspective view of a three-dimensional terrain model shows the shape of the 'Columbia Hills' landscape where NASA's Mars Exploration Rover Spirit has been working since mid-2004. North is toward the lower left. 'Husband Hill' is at the center, with the 'Inner Basin' behind it. This view is from images taken by the Mars Orbiter Camera on NASA's Mars Global Surveyor and processed into a three-dimensional terrain model by the U.S. Geological Survey.

    Spirit's Long Journey, Sol 450 More than 15 months after landing on Mars, NASA's Spirit rover is still going strong, having traveled a total of 4,276 meters (2.66 miles) as of martian day, or sol, 450 (April 8, 2005). This is a perspective view of the steepness of the 'Columbia Hills,' showing sites nicknamed 'Tennessee Valley,' 'Larry's Lookout,' 'Inner Basin,' 'Home Plate,' and the basin and summit beyond. This orbital view comprises images taken by the Mars Orbiter Camera on NASA's Mars Global Surveyor and processed by the U.S. Geological Survey as a three-dimensional terrain model.

  17. 'Columbia Hills' from Orbit

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This view of the 'Columbia Hills' in Gusev Crater was made by draping an image from the Mars Orbiter Camera on NASA's Mars Global Surveyor orbiter (image E0300012 from that camera) over a digital elevation model that was derived from two Mars Orbiter Camera images (E0300012 and R0200357).

    This unique view is helpful to the rover team members as they plan the journey of NASA's Mars Exploration Rover Spirit to the base of the Columbia Hills and beyond. Spirit successfully completed a three-month primary mission, and so far remains healthy in an extended mission of bonus exploration. As of sol 135 (on May 21, 2004), Spirit sits approximately 680 meters (0.4 miles) away from its first target at the western base of the hills, a spot informally called 'West Spur.' The team estimates that Spirit will reach West Spur by sol 146 (June 1, 2004). Spirit will most likely remain there for about a week to study the outcrops and rocks associated with this location.

    When done there, Spirit will head approximately 620 meters (0.38 miles) to a higher-elevation location informally called 'Lookout Point.' Spirit might reach Lookout Point by around sol 165 (June 20, 2004). On the way, the rover will pass by and study ripple-shaped wind deposits that may reveal more information about wind processes on Mars.

    Lookout Point will provide a great vantage point for scientists to remotely study the inner basin area of the Columbia Hills. This basin contains a broad range of interesting geological targets including the informally named 'Home Plate' and other possible layered outcrops. These features suggest that the hills contain rock layers. Spirit might investigate the layers to determine whether they are water-deposited sedimentary rock.

    Once at Lookout Point, Spirit will acquire 360-degree panoramic images of the entire area to help define the rover's next steps. Assuming the rover stays healthy, Spirit will eventually drive down into the basin to get an up

  18. Last Glacial Maximum and deglacial abyssal seawater oxygen isotopic ratios

    NASA Astrophysics Data System (ADS)

    Wunsch, Carl

    2016-06-01

    An earlier analysis of pore-water salinity (chlorinity) in two deep-sea cores, using terminal constraint methods of control theory, concluded that although a salinity amplification in the abyss was possible during the LGM, it was not required by the data. Here the same methodology is applied to δ18Ow in the upper 100 m of four deep-sea cores. An ice volume amplification to the isotopic ratio is, again, consistent with the data but not required by it. In particular, results are very sensitive, with conventional diffusion values, to the assumed initial conditions at -100 ky and a long list of noise (uncertainty) assumptions. If the calcite values of δ18O are fully reliable, then published enriched values of the ratio in seawater are necessary to preclude sub-freezing temperatures, but the seawater δ18O in pore fluids does not independently require the conclusion.

  19. KISATCHIE HILLS WILDERNESS, LOUISIANA.

    USGS Publications Warehouse

    Haley, Boyd R.; Ryan, George S.

    1984-01-01

    A mineral-resource survey of the Kisatchie Hills Wilderness, Louisiana indicated little promise for the occurrence of mineral resources. There is insufficient data on oil and gas producing formations that underlie the area to evaluate the oil and gas resource potential. All the oil fields of Wilcox age are less than 40 acres in extent; therefore, closer spaced deeper wells might find additional fields in sediments of Wilcox age. Oil and natural gas have been produced from older reservoirs (Cretaceous age) to the northwest of the wilderness, and deeper wells might find oil and natural gas in sediments of Cretaceous and older age in the vicinity of the wilderness.

  20. Cooperativity: over the Hill.

    PubMed

    Forsén, S; Linse, S

    1995-12-01

    Cooperativity, the ability of ligand binding at one site on a macromolecule to influence ligand binding at a different site on the same macromolecule, is a fascinating biological property that is often poorly explained in textbooks. The Hill coefficient is commonly used in biophysical studies of cooperative systems although it is not a quantitative measure of cooperativity. The free energy of interaction between binding sites (delta delta G) is a more stringent definition of cooperativity and provides a direct quantitative measure of how the binding of ligand at one site affects the ligand affinity of another site. PMID:8571449

  1. [The role of antarctica in formation of the cenozoic climate and contemporary open sea abyssal fauna].

    PubMed

    Kuznetsov, A P

    2001-01-01

    The key role of the Antarctic continent in the formation of the contemporary (Cenozoic) zonal-contrast climate and related geologically "young" (Postmesozoic) contemporary abyssal fauna of the World Ocean is discussed on the basis of the current concepts of pleitectonics, history of planetary climates, paleobiooceanology, and bioevolution. It has been shown that the flows of cold aerated near-Antarctic waters that started to descend in the open sea abyssal in the middle of Cenozoic were capable of substituting for previously (in Mesozoic) heated (up to 15-20 degrees C) abyssal waters within only 1500-2000 years. Following the descending near-Antarctic waters, the shallow and cold water oxyphilic fauna assimilated the abyssal zone that had been warm water and weakly populated. PMID:15926327

  2. 3D Model of the McGinness Hills Geothermal Area

    DOE Data Explorer

    Faulds, James E.

    2013-12-31

    The McGinness Hills geothermal system lies in a ~8.5 km wide, north-northeast trending accommodation zone defined by east-dipping normal faults bounding the Toiyabe Range to the west and west-dipping normal faults bounding the Simpson Park Mountains to the east. Within this broad accommodation zone lies a fault step-over defined by north-northeast striking, west-dipping normal faults which step to the left at roughly the latitude of the McGinness Hills geothermal system. The McGinness Hills 3D model consists of 9 geologic units and 41 faults. The basal geologic units are metasediments of the Ordovician Valmy and Vininni Formations (undifferentiated in the model) which are intruded by Jurassic granitic rocks. Unconformably overlying is a ~100s m-thick section of Tertiary andesitic lava flows and four Oligocene-to-Miocene ash-flow tuffs: The Rattlesnake Canyon Tuff, tuff of Sutcliffe, the Cambell Creek Tuff and the Nine Hill tuff. Overlying are sequences of pre-to-syn-extensional Quaternary alluvium and post-extensional Quaternary alluvium. 10-15º eastward dip of the Tertiary stratigraphy is controlled by the predominant west-dipping fault set. Geothermal production comes from two west dipping normal faults in the northern limb of the step over. Injection is into west dipping faults in the southern limb of the step over. Production and injection sites are in hydrologic communication, but at a deep level, as the northwest striking fault that links the southern and northern limbs of the step-over has no permeability.

  3. Abyssal Sequestration of Nuclear Waste in Earth's Crust

    NASA Astrophysics Data System (ADS)

    Germanovich, L. N.; Garagash, D.; Murdoch, L. C.; Robinowitz, M.

    2013-12-01

    This work outlines a new method for disposing of hazardous (e.g., nuclear) waste. The technique is called Abyssal Sequestration, and it involves placing the waste at extreme depths in Earth's crust where it could achieve the geologically-long period of isolation. Abyssal Sequestration involves storing the waste in hydraulic fractures driven by gravity, a process we term gravity fracturing. In short, we suggest creating a dense fluid (slurry) containing waste, introducing the fluid into a fracture, and extending the fracture downward until it becomes long enough to propagate independently. The fracture will continue to propagate downward to great depth, permanently isolating the waste. Storing solid wastes by mixing them with fluids and injecting them into hydraulic fractures is a well-known technology. The essence of our idea differs from conventional hydraulic fracturing techniques only slightly in that it uses fracturing fluid heavier than the surrounding rock. This difference is fundamental, however, because it allows hydraulic fractures to propagate downward and carry wastes by gravity instead of or in addition to being injected by pumping. An example of similar gravity-driven fractures with positive buoyancy is given by magmatic dikes that may serve as an analog of Abyssal Sequestration occurring in nature. Mechanics of fracture propagation in conditions of positive (diking) and negative (heavy waste slurry) buoyancy is similar and considered in this work for both cases. Analog experiments in gelatin show that fracture breadth (horizontal dimension) remains nearly stationary when fracturing process in the fracture 'head' (where breadth is 'created') is dominated by solid toughness, as opposed to the viscous fluid dissipation dominant in the fracture tail. We model propagation of the resulting 'buoyant' or 'sinking' finger-like fracture of stationary breadth with slowly varying opening along the crack length. The elastic response of the crack to fluid loading

  4. Lost Hills, California Interferogram

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This figure shows a comparison of interferograms from four different years mapping the rapid ground subsidence over the Lost Hills oil field in California. Lost Hills is located about 60 km (40 miles) northwest of Bakersfield in the San Joaquin Valley. The oilfield is about 1.5 km (1 mile) wide and 6 km (3.5 miles) long. Each interferogram was created using pairs of images taken by synthetic aperture radar that have been combined to measure surface deformation or changes that may have occurred in the time between when data for the two images were taken. The images were collected by the European Space Agency's Remote Sensing satellites (ERS-1 and ERS-2) in two months of each year shown (1995, 1996, 1998 and 1999) and were combined to produce these image maps of the apparent surface deformation, or changes. The interferometric measurements that show the changes, primarily vertical subsidence of the surface, are rendered in color with purple indicating no motion and the brightest red showing rapid subsidence. The white areas are where the radar measurements could not be obtained, mostly in the agricultural fields around the oilfields where plant growth or plowing altered the radar properties of the surface. These radar data show that parts of the oilfield were subsiding unusually rapidly, more than 3 centimenters (1.2 inches) a month, in 1995 and 1996. They also reveal that while the ground subsidence rate decreased in the center part of the oilfield, it increased in the northern part between 1995 and 1996 and 1998 and 1999. Subsidence maps like these combined with records of oil and water extraction and injection will help scientist understand how the rocks within an oilfield are behaving, leading to improvements in oilfield operations. For more information, read Radar Helps Monitor Oil Fields. Images courtesy Eric Fielding, NASA Jet Propulsion Laboratory

  5. Lost Hills, California Interferogram

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This figure shows a comparison of interferograms from four different years mapping the rapid ground subsidence over the Lost Hills oil field in California. Lost Hills is located about 60 km (40 miles) northwest of Bakersfield in the San Joaquin Valley. The oil field is about 1.5 km (1mile) wide and 6 km (3.5 miles) long.

    Each interferogram was created using pairs of images taken by synthetic aperture radar that have been combined to measure surface deformation or changes that may have occurred in the time between when data for the two images were taken. The images were collected by the European Space Agency's Remote Sensing satellites (ERS-1 and ERS-2) in two months of each year shown (1995, 1996, 1998 and 1999) and were combined to produce these image maps of the apparent surface deformation, or changes.

    The interferometric measurements that show the changes, primarily vertical subsidence of the surface, are rendered in color with purple indicating no motion and the brightest red showing rapid subsidence. The white areas are where the radar measurements could not be obtained, mostly in the agricultural fields around the oil fields where plant growth or plowing altered the radar properties of the surface.

    These radar data show that parts of the oil field were subsiding unusually rapidly, more than 3 centimeters (1.2 inches) a month, in 1995 and 1996. They also reveal that while the ground subsidence rate decreased in the center part of the oil field, it increased in the northern part between 1995 and 1996 and 1998 and 1999.

    Subsidence maps like these combined with records of oil and water extraction and injection will help scientist understand how the rocks within an oil field are behaving, leading to improvements in oil field operations.

  6. Zipper Faults

    NASA Astrophysics Data System (ADS)

    Platt, J. P.; Passchier, C. W.

    2015-12-01

    Intersecting simultaneously active pairs of faults with different orientations and opposing slip sense ("conjugate faults") present geometrical and kinematic problems. Such faults rarely offset each other, even when they have displacements of many km. A simple solution to the problem is that the two faults merge, either zippering up or unzippering, depending on the relationship between the angle of intersection and the slip senses. A widely recognized example of this is the so-called blind front developed in some thrust belts, where a backthrust branches off a decollement surface at depth. The decollement progressively unzippers, so that its hanging wall becomes the hanging wall of the backthrust, and its footwall becomes the footwall of the active decollement. The opposite situation commonly arises in core complexes, where conjugate low-angle normal faults merge to form a single detachment; in this case the two faults zipper up. Analogous situations may arise for conjugate pairs of strike-slip faults. We present kinematic and geometrical analyses of the Garlock and San Andreas faults in California, the Najd fault system in Saudi Arabia, the North and East Anatolian faults, the Karakoram and Altyn Tagh faults in Tibet, and the Tonale and Guidicarie faults in the southern Alps, all of which appear to have undergone zippering over distances of several tens to hundreds of km. The zippering process may produce complex and significant patterns of strain and rotation in the surrounding rocks, particularly if the angle between the zippered faults is large. A zippering fault may be inactive during active movement on the intersecting faults, or it may have a slip rate that differs from either fault. Intersecting conjugate ductile shear zones behave in the same way on outcrop and micro-scales.

  7. The Mud Hills, Mojave Desert, California: Structure, stratigraphy and sedimentology of a rapidly extended terrane

    SciTech Connect

    Ingersoll, R.V.; Devaney, K.A.; Geslin, J.K.; Cavazza, W.; Diamond, D.S.; Jagiello, K.J.; Marsaglia, K.M.; Paylor, E.D. II; Short, P.F. . Dept. of Earth and Space Sciences)

    1993-04-01

    The Mud Hills exposes synorogenic breccia (Mud Hills Fm.) deposited during the final stages of crustal extension of the upper plate above the Waterman Hills detachment (20--18 Ma). Previous workers have misinterpreted fault contacts as stratigraphic contacts, and have developed intricate pseudostratigraphy to explain their observations. The authors' detailed mapping, combined with stratigraphic and sedimentologic data, documents that the volcaniclastic Pickhandle Fm. is conformably overlain by the plutoniclastic Mud Hills Fm., with no interfingering. Repetition of these south-dipping lithologic units is due to imbricate, north-dipping listric faults. These relations are demonstrated by the systematic northward v''ing of fault contacts and southward v''ing of stratigraphic contacts. Stratigraphic dip decreases upsection, which is consistent with incremental rotation of basinal strata simultaneously with deposition. Most of the Mud Hills Fm. consists of rock-avalanche breccia and megabreccia derived from granodiorite, which is identical to basement exposed beneath the Pickhandle and Jackhammer Fms. to the north. The Mud Hills Fm. was derived from now-buried granodiorite of a stranded upper-plate block to the south, as demonstrated by northward paleocurrents, facies relations and the presence of fine-grained units close to the presumed master fault (as is typical of half-graben sedimentation). Unconformably overlying the Mud Hills Fm. is the Owl Conglomerate (Barstow Fm.), which has mixed provenance with southward paleocurrents; the Owl Conglomerate was derived from residual highlands after extension ceased. Integration of structural, stratigraphic and sedimentologic information is essential for correct reconstruction of highly extended terranes.

  8. 19. View of second floor of the Cherry Hill lettuce ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. View of second floor of the Cherry Hill lettuce shed looking at door to stairwell - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  9. 18. View of the second floor of the Cherry Hill ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. View of the second floor of the Cherry Hill lettuce shed looking at door - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  10. 15. Interior view of Cherry Hill lettuce shed showing posts ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. Interior view of Cherry Hill lettuce shed showing posts looking towards the chute building - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  11. 20. View of second floor to the Cherry Hill lettuce ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. View of second floor to the Cherry Hill lettuce shed looking at floor area - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  12. 14. Interior view of Cherry Hill lettuce shed looking towards ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. Interior view of Cherry Hill lettuce shed looking towards chute building - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  13. 9. View of Cherry Hill lettuce shed looking north, with ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. View of Cherry Hill lettuce shed looking north, with chute building on the left - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  14. 3. View of Cherry Hill lettuce shed looking southeast; parking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. View of Cherry Hill lettuce shed looking southeast; parking lot in foreground - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  15. 12. Partial view of Cherry Hill lettuce shed looking northwest ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. Partial view of Cherry Hill lettuce shed looking northwest showing office - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  16. 2. Oblique view of Cherry Hill lettuce shed looking south; ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Oblique view of Cherry Hill lettuce shed looking south; chute building is in background - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  17. 6. Oblique view of Cherry Hill lettuce shed looking northeast, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Oblique view of Cherry Hill lettuce shed looking northeast, with chute building to the right - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  18. 16. Interior view of Cherry Hill lettuce shed looking up ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. Interior view of Cherry Hill lettuce shed looking up at the trusses of the second floor - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  19. 21. View of second floor of the Cherry Hill lettuce ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. View of second floor of the Cherry Hill lettuce shed looking towards window - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  20. 22. View of second floor of the Cherry Hill lettuce ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    22. View of second floor of the Cherry Hill lettuce shed looking at double doors - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  1. Abyssal echinoid and asteroid fauna of the North Pacific

    NASA Astrophysics Data System (ADS)

    Mironov, A. N.; Minin, K. V.; Dilman, A. B.

    2015-01-01

    Echinoidea and Asteroidea collected in the Kuril-Kamchatka Trench area by the KuramBio Expedition were examined. Altogether 20 species belonging to 16 genera were found, among them six species and two genera were recorded in the North Pacific for the first time. Morphological variability of Abyssaster tara suggests that this species is congeneric with Styracaster transitivus and Styracaster paucispinus. Complete age series of the echinoid Echinosigra amphora and the asteroid Eremicaster crassus are described. The juveniles of E. amphora (>0.5 mm in length) are characterized by unique ophicephalous pedicellaria in the centre of aboral side of the test. The abyssal echinoid and asteroid fauna of the North Pacific (north of 30°N and deeper than 3000 m) comprises 62 species of 36 genera; 22 species (35%) and 3 genera are endemic to this region. Global distribution patterns of genera support the hypothesis that there were two stages of dispersal from the Antarctic to the North Pacific: at earlier stage the dispersal occurred via the East Pacific and at the later stage - via the West Pacific. The genera that had dispersed at earlier stage are represented only in the North and East Pacific and Antarctic. Distribution ranges of these genera in the East Pacific are limited to the narrow zone extending meridionally along the base of the American continental slope. Genera with such distribution pattern are likely adapted to highly eutrophic conditions.

  2. Diversity and Biogeography of Bathyal and Abyssal Seafloor Bacteria

    PubMed Central

    Bienhold, Christina; Zinger, Lucie; Boetius, Antje; Ramette, Alban

    2016-01-01

    The deep ocean floor covers more than 60% of the Earth’s surface, and hosts diverse bacterial communities with important functions in carbon and nutrient cycles. The identification of key bacterial members remains a challenge and their patterns of distribution in seafloor sediment yet remain poorly described. Previous studies were either regionally restricted or included few deep-sea sediments, and did not specifically test biogeographic patterns across the vast oligotrophic bathyal and abyssal seafloor. Here we define the composition of this deep seafloor microbiome by describing those bacterial operational taxonomic units (OTU) that are specifically associated with deep-sea surface sediments at water depths ranging from 1000–5300 m. We show that the microbiome of the surface seafloor is distinct from the subsurface seafloor. The cosmopolitan bacterial OTU were affiliated with the clades JTB255 (class Gammaproteobacteria, order Xanthomonadales) and OM1 (Actinobacteria, order Acidimicrobiales), comprising 21% and 7% of their respective clades, and about 1% of all sequences in the study. Overall, few sequence-abundant bacterial types were globally dispersed and displayed positive range-abundance relationships. Most bacterial populations were rare and exhibited a high degree of endemism, explaining the substantial differences in community composition observed over large spatial scales. Despite the relative physicochemical uniformity of deep-sea sediments, we identified indicators of productivity regimes, especially sediment organic matter content, as factors significantly associated with changes in bacterial community structure across the globe. PMID:26814838

  3. Diversity and Biogeography of Bathyal and Abyssal Seafloor Bacteria.

    PubMed

    Bienhold, Christina; Zinger, Lucie; Boetius, Antje; Ramette, Alban

    2016-01-01

    The deep ocean floor covers more than 60% of the Earth's surface, and hosts diverse bacterial communities with important functions in carbon and nutrient cycles. The identification of key bacterial members remains a challenge and their patterns of distribution in seafloor sediment yet remain poorly described. Previous studies were either regionally restricted or included few deep-sea sediments, and did not specifically test biogeographic patterns across the vast oligotrophic bathyal and abyssal seafloor. Here we define the composition of this deep seafloor microbiome by describing those bacterial operational taxonomic units (OTU) that are specifically associated with deep-sea surface sediments at water depths ranging from 1000-5300 m. We show that the microbiome of the surface seafloor is distinct from the subsurface seafloor. The cosmopolitan bacterial OTU were affiliated with the clades JTB255 (class Gammaproteobacteria, order Xanthomonadales) and OM1 (Actinobacteria, order Acidimicrobiales), comprising 21% and 7% of their respective clades, and about 1% of all sequences in the study. Overall, few sequence-abundant bacterial types were globally dispersed and displayed positive range-abundance relationships. Most bacterial populations were rare and exhibited a high degree of endemism, explaining the substantial differences in community composition observed over large spatial scales. Despite the relative physicochemical uniformity of deep-sea sediments, we identified indicators of productivity regimes, especially sediment organic matter content, as factors significantly associated with changes in bacterial community structure across the globe. PMID:26814838

  4. Fault finder

    DOEpatents

    Bunch, Richard H.

    1986-01-01

    A fault finder for locating faults along a high voltage electrical transmission line. Real time monitoring of background noise and improved filtering of input signals is used to identify the occurrence of a fault. A fault is detected at both a master and remote unit spaced along the line. A master clock synchronizes operation of a similar clock at the remote unit. Both units include modulator and demodulator circuits for transmission of clock signals and data. All data is received at the master unit for processing to determine an accurate fault distance calculation.

  5. Slip on faults in the Imperial Valley Triggered by the 4 April 2010 Mw 7.2 El Major earthquake as revealed by InSAR

    NASA Astrophysics Data System (ADS)

    Wei, M.; Sandwell, D. T.; Fialko, Y.; Bilham, R. G.

    2010-12-01

    Radar interferometry (InSAR) reveals surface slip on multiple faults in the Imperial Valley triggered by the 2010 Baja M7.2 earthquake. Co-seismic offsets occurred on the San Andreas, Superstition Hills, Imperial, Elmore Ranch, Wienert, Coyote Creek, Elsinore, Yuha Wells, and several minor faults near the town of Ocotillo at the northern end of the mainshock rupture. We documented right-lateral slip (< 40 mm) on northwest trending faults and left-lateral slip (< 40 mm) on southwest trending faults. Slip occurred on 15-km- and 20-km-long segments of the San Andreas Fault in the Mecca Hills (≤ 50 mm) and Durmid Hill (≤ 10 mm) respectively, and 23 km of the Superstition Hills Fault (≤ 37 mm). Field measurements of slip on the Superstition Hills Fault agree with InSAR and creepmeter measurements to within a few millimeters. Dislocation models of the InSAR data on the Superstition Hills Fault confirm that creep in this sequence, as in previous slip events, is confined to shallow depths (< 3 km). Map of Southern California and Northern Baja California. Black solid lines are major faults. Yellow solid lines are faults with observed offsets. Dashed black lines are National and State borders. White star is the epicenter of the 2010 April 4th El Major earthquake. Red dots are aftershocks within one month after the main rupture with magnitude greater than 5, blue 4-5, and green 3-4. Earthquake data are from the Southern California Earthquake Center. Fault names are abbreviated as follows: ERF, Elmore Ranch fault; SHF, Superstition Hills fault; SMF, Superstition Mountains fault; WF, Wienert fault; YWF, Yuha Wells Fault.

  6. Eukaryotic Richness in the Abyss: Insights from Pyrotag Sequencing

    PubMed Central

    Pawlowski, Jan; Christen, Richard; Lecroq, Béatrice; Bachar, Dipankar; Shahbazkia, Hamid Reza; Amaral-Zettler, Linda; Guillou, Laure

    2011-01-01

    Background The deep sea floor is considered one of the most diverse ecosystems on Earth. Recent environmental DNA surveys based on clone libraries of rRNA genes confirm this observation and reveal a high diversity of eukaryotes present in deep-sea sediment samples. However, environmental clone-library surveys yield only a modest number of sequences with which to evaluate the diversity of abyssal eukaryotes. Methodology/Principal Findings Here, we examined the richness of eukaryotic DNA in deep Arctic and Southern Ocean samples using massively parallel sequencing of the 18S ribosomal RNA (rRNA) V9 hypervariable region. In very small volumes of sediments, ranging from 0.35 to 0.7 g, we recovered up to 7,499 unique sequences per sample. By clustering sequences having up to 3 differences, we observed from 942 to 1756 Operational Taxonomic Units (OTUs) per sample. Taxonomic analyses of these OTUs showed that DNA of all major groups of eukaryotes is represented at the deep-sea floor. The dinoflagellates, cercozoans, ciliates, and euglenozoans predominate, contributing to 17%, 16%, 10%, and 8% of all assigned OTUs, respectively. Interestingly, many sequences represent photosynthetic taxa or are similar to those reported from the environmental surveys of surface waters. Moreover, each sample contained from 31 to 71 different metazoan OTUs despite the small sample volume collected. This indicates that a significant faction of the eukaryotic DNA sequences likely do not belong to living organisms, but represent either free, extracellular DNA or remains and resting stages of planktonic species. Conclusions/Significance In view of our study, the deep-sea floor appears as a global DNA repository, which preserves genetic information about organisms living in the sediment, as well as in the water column above it. This information can be used for future monitoring of past and present environmental changes. PMID:21483744

  7. Buried-hill discoveries in Damintan depression of North China basin

    SciTech Connect

    Xiaoguang, T.; Zuan, H.

    1988-01-01

    The Damintan fault depression is about 20 km west of Shenyang, Liaoning Province, North China, and is a small Tertiary continental depression, covering only about 800 km/sup 2/. In the depression, the Tertiary system unconformably overlies upper-middle Proterozoic sedimentary rocks and Archean metamorphic rocks. The Tertiary system is up to 6,600 m in thickness. Source rocks are in the third and fourth members of the Eocens Shahejie Formation. Buried-hill traps were formed in Proterozoic carbonates and metamorphic rocks of the Archean. Fault block, stratigraphic, and lithologic traps also occur in sandstones of the Shahejie Formation, especially in those of the third member. Several buried-hill-drape traps occur in the depression. The various types of oil pole in each buried-hill-drape trap constitute a complex hydrocarbon accumulation zone. A series of oil fields have been found in the depression. The crude oil is characterized by high wax content and high pour point.

  8. Edwardsia sojabio sp. n. (Cnidaria: Anthozoa: Actiniaria: Edwardsiidae), a new abyssal sea anemone from the Sea ofJapan

    NASA Astrophysics Data System (ADS)

    Sanamyan, Nadya; Sanamyan, Karen

    2013-02-01

    The paper describes new deep-water edwardsiid sea anemone Edwardsia sojabio sp. n. which is very common on soft muddy bottoms at lower bathyal and upper abyssal depths in the Sea of Japan. It was recorded in high quantity in depths between 2545 and 3550 m and is the second abyssal species of the genus Edwardsia.

  9. Epithermal neutron activation analysis investigation of Clarion-Clipperton abyssal plane clay and polymetallic micronodules.

    PubMed

    Duliu, O G; Cristache, C I; Culicovc, O A; Frontasyeva, M V; Szobotca, S A; Toma, M

    2009-05-01

    The content of seven major (Na, Al, Cl, Mn, K, Ca, Ti, Fe) and 30 trace (Sc, V, Cr, Ni, Co, Zn, Cu, As, Sr, Rb, Zr, Mo, Sn, In, Sb, Ba, Cs, La, Ce, Nd, Eu, Sm, Tb, Dy, Yb, Hf, Ta, W, Th, U) elements determined by INAA in 13 samples of abyssal clay and two samples of micronodules collected from the North pacific Ocean Clarion-Clipperton abyssal plane is presented and discussed with respect to some rocks models. PMID:19230682

  10. Soufriere Hills Volcano

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In this ASTER image of Soufriere Hills Volcano on Montserrat in the Caribbean, continued eruptive activity is evident by the extensive smoke and ash plume streaming towards the west-southwest. Significant eruptive activity began in 1995, forcing the authorities to evacuate more than 7,000 of the island's original population of 11,000. The primary risk now is to the northern part of the island and to the airport. Small rockfalls and pyroclastic flows (ash, rock and hot gases) are common at this time due to continued growth of the dome at the volcano's summit.

    This image was acquired on October 29, 2002 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

    Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader; Bjorn Eng of JPL is the project manager. The Terra mission is

  11. Fault zone amplified waves as a possible seismic hazard along the Calaveras fault in central California

    USGS Publications Warehouse

    Spudich, P.; Olsen, K.B.

    2001-01-01

    The Calaveras fault lies within a low velocity zone (LVZ) 1-2 km wide near Gilroy, California. Accelerographs G06, located in the LVZ 1.2 km from the Calaveras fault, and G07, 4 km from G06, recorded both the M 6.2 1984 Morgan Hill and the M 6.9 1989 Loma Prieta earthquakes. Comparison of the ground motions shows that a large 0.6-1.0 Hz velocity pulse observed at G06 during the Morgan Hill event may be amplified by focussing caused by the LVZ. Such amplified waves might be a mappable seismic hazard, and the zone of increased hazard can extend as much as 1.2 km from the surface trace of the fault. Finite-difference simulations of ground motions in a simplified LVZ model show a zone of amplified motion similar to the observations.

  12. Oxygen Fugacity of Abyssal Peridotites Along the Gakkel Ridge

    NASA Astrophysics Data System (ADS)

    Said, M.; Birner, S.; Cottrell, E.

    2015-12-01

    The oxygen budget of the Earth's mantle is important in understanding how our planet evolves chemically over time. The Gakkel Ridge is the world's slowest spreading ridge [1], and exposes peridotites along its axis that record the activity of oxygen in the upper mantle. Our samples comprise relatively fertile lherzolites and harzburgites (Cr#=0.13-0.17, 3.1-8.3% modal cpx [2]) as well as refractory harzburgites (Cr#=0.43-0.55, 0.2-1.0% modal cpx [2]). Using spinel peridotite oxygen barometry [3], we calculated the oxygen fugacity (fO2) of a suite of 10 peridotites from the Gakkel Ridge in order to investigate how melt processes affect the oxygen budget of the Earth's interior. We show that the low-Cr# lherzolites and harzburgites range from -0.1 to +0.6 log units relative to the QFM buffer, consistent with the global abyssal peridotite array, whereas high-Cr# refractory harzburgites have low fO2 values, ranging from -0.7 to -2.7 log units below QFM, with the most refractory samples falling significantly lower than the global array. Because D'Errico et al. (submitted) interprets the refractory samples as recording ancient melt extraction, the low fO2 recorded by these samples may originate in the geologic past, perhaps even in a different tectonic setting. While LREE enrichment in the refractory harzburgites [2] provides evidence for refertilization by an infiltrating melt that could have recently imprinted reducing conditions, we see no corresponding increase in TiO2 content in the spinels, which weakens this hypothesis. Further research on additional refractory harzburgites is needed to constrain whether the reduced nature of these samples is telling us something about the effect of extreme melt extraction on fO2 at ridges, or whether these samples record a unique history that obscures processes operating at ridges today. [1] Coakley and Cochran, EPSL (1998), [2] D'Errico et al., submitted, [3] Bryndzia and Wood, American Journal of Science (1990)

  13. Variability in ultraplankton at the Porcupine Abyssal Plain study site

    NASA Astrophysics Data System (ADS)

    Martin, Adrian P.; Zubkov, Mikhail V.; Holland, Ross J.; Tarran, Glen; Burkill, Peter

    2010-08-01

    Observations of the ultraplankton (<5 μm) are presented from a 4 day mesoscale survey centred on the Porcupine Abyssal Plain (PAP) study site (49°00'N 16°30'W), in July 2006. The organisms enumerated include two groups of phytoplankton, Synechococcus cyanobacteria, heterotrophic bacteria, large viruses, and two size classes of heterotrophic protist. The dataset comprises over 400 samples from the mixed layer taken over a 100 × 100 km 2 area at a spatial resolution of typically 2-3 km. For phytoplankton and heterotrophic bacteria there is a clear bimodal structure to the histograms of abundance indicative of two distinct communities in the region. Using the strong bimodality of one of the phytoplankton groups' histogram as a basis, the dataset is split into two subsets, with roughly 200 points in each, corresponding to the two histogram peaks. Doing so provides evidence that Synechococcus and viruses may also have a bimodal structure. Correlations between all pairings of these five organisms (both phytoplankton groups, Synechococcus, heterotrophic bacteria and viruses) are positive and quite high (r>0.7). The two communities can therefore be characterised as high and low abundance. Although there is a coincidence of low abundances with high temperatures in the southwest corner of the region, where there was known to be an eddy present, the spatial distributions of these organisms over the whole region is poorly predicted by temperature (or salinity or density). Furthermore, the spatial distributions of heterotrophic protists are found to differ strongly from those of the other organisms, having a unimodal structure and no obvious large scale structure. The more random structure of the heterotrophs' spatial distribution compared to their prey is consistent with previous results from the continental shelf, but is demonstrated for the open ocean here for the first time. Spatial variability is a large potential source of error in point samples, such as those

  14. Oligocene to Miocene carbon isotope cycles and abyssal circulation changes

    NASA Astrophysics Data System (ADS)

    Miller, Kenneth G.; Fairbanks, Richard G.

    Three cycles of δ13C occurred in Oligocene to Miocene benthic and planktonic foraminifera at western North Atlantic Sites 558 and 563. Intervals of high δ13C occurred at about 35-33 Ma (early Oligocene), 25-22 Ma (across the Oligocene/Miocene boundary), and 18-14 Ma (across the early/middle Miocene boundary). Similar carbon isotopic fluctuations have been measured in benthic and planktonic foraminifera from the Atlantic, Pacific, and Indian oceans, suggesting that these cycles represent global changes in the δ13C of mean ocean water. The average duration of the carbon cycles is 50 times greater than the residence time of carbon in the oceans. Therefore, the mechanism controlling these cycles must be tied to changes in the input ratio of organic carbon to carbonate from weathering rocks or to changes in the output ratio of organic carbon to carbonate in marine sediments. Following a strategy used to study modern and Pleistocene oceans, benthic foraminiferal δ13C differences between the Atlantic and Pacific are used to infer Oligocene through Miocene abyssal circulation changes. The Atlantic was most enriched in l3C relative to the Pacific from about 36-33 Ma (early Oligocene) and 26-10 Ma (late Oligocene to late Miocene). We interpret this as indicating supply of nutrient-depleted bottom water in the North Atlantic, perhaps analogous to modern North Atlantic Deep Water. High benthic foraminiferal δ13O values at about 36-35 Ma, 31-28 Ma, 25-24 Ma, and younger than 15 Ma indicate the presence of ice sheets at these times. Covariance between benthic and planktonic foraminiferal δ18O records of 0.3-0.5°/ºº at 36 Ma, 31 Ma, and 25 Ma suggests that three periods of continental glaciation caused eustatic (global sea-level) lowerings of 30-50 m during the Oligocene epoch. The δ13C cycles do not correlate with sea-level changes deduced from oxygen isotopic data, nor do they correlate with other proxy indicators for sea level.

  15. Major and trace element distributions in manganese nodules and micronodules as well as abyssal clay from the Clarion-Clipperton abyssal plain, Northeast Pacific

    NASA Astrophysics Data System (ADS)

    Duliu, O. G.; Alexe, V.; Moutte, J.; Szobotca, S. A.

    2009-04-01

    The contents of seven major components (TiO2, Fe2O3, MgO, CaO, Na2O, K2O and P2O5) and 15 trace elements (Sc, V, Cr, Ni, Cu, Sr, Y, Zr, Ba, La, Ce, Nd, Eu, Yb and Th) were determined by ICP-AE spectrometry in 27 samples of manganese nodules, micronodules as well as abyssal clay collected by dredging from an area of nearly 1,9802 nautical miles in the central Clarion-Clipperton abyssal plain at a depth of about 4,500 m. Statistical analyses were used to compare among individual as well as pooled datasets, in addition to different indicators such as La/Th, Ni/Cu and LREE/HREE ratios for the Clarion-Clipperton samples, as well as between these and corresponding values for the upper continental crust (UCC), North America Shale Composite (NASC), and igneous Indian and Pacific Mid-Ocean Ridge Basalts (MORBs). The results show significant correlations between major components in the Clarion-Clipperton samples and Pacific Ocean MORB, whereas trace elements (excepting Ni and Cu) correlate better with the UCC and NASC. There is also depletion in LREEs, together with a Ce negative anomaly for all Clarion-Clipperton samples. The nodule, micronodule and abyssal clay datasets each reveal typical clusters of components such as P2O5 and Y, La, Nd, Eu, Tb, or Ni and Cu. Compared to abyssal clay, the nodule as well as micronodules show significant enrichment in Ni and Cu; nevertheless, an essentially constant Ni/Cu ratio indicates that all samples come from the sediment surface. The distributions of major components as well as trace elements for the Clarion-Clipperton samples present, to different degrees, characteristics common to both the upper continental crust and Mid-Ocean Ridge Basalt, strongly implying a hydrothermal origin, most probably from East Pacific Rise material transported by the Pacific North Equatorial Current.

  16. Boundary Element Modeling of Fault Cored Anticlines and Associated Blind Thrust Faults in Central California

    NASA Astrophysics Data System (ADS)

    Williams, M. K.; Johnson, K. M.

    2015-12-01

    Recent literature investigating active folding indicates that crustal-scale anticlines grow primarily through slip on underlying faults. Such studies use the geometry and uplift rates of active fault-related folds to infer fault slip rate based upon an assumed kinematic relationship between fault slip and particle motion in the surrounding crust. Our method uses a boundary element model of flexural slip folding called BEAFS (Boundary Element Analysis of Flexural Slip), allowing us to focus on the mechanics of deformation.In many cases, the shallow geometry (<5km) of natural folds are well constrained by subsurface data. However, the geometry of the causative blind thrust faults are often not well imaged. By comparing our numerical simulations with published subsurface and surface data on naturally occurring active folds, we can determine fault geometry and the extent to which various mechanisms are controlling fold evolution. For this work, we present our model results for the underlying faults at Kettleman Hills South Dome, Kettleman Hills North Dome, and Coalinga Anticline in the San Joaquin Valley of Central California. The rupturing of blind thrust faults associated with actively growing anticlines such as these pose a significant global seismic hazard. Our study area is of particular interest as it is the site of two such recent earthquakes—a Mw=6.5 earthquake in 1983 at Coalinga and a Mw=6.1 in 1985 at Kettleman Hills North Dome. Thus, we can compare the published earthquake data from these events to the parameters predicted by our model results from BEAFS.

  17. Subsurface structure and hydrocarbon occurrence, Heidelberg-Sand Hill graben system, southeast Mississippi

    SciTech Connect

    Bowman, J.K.; Meylan, M.A.

    1986-09-01

    The subsurface structure and hydrocarbon distribution of the Heidelberg-Sand Hill graben system have been determined using 575 electric logs, existing field studies, and proprietary seismic data. This graben system, located on the eastern side of the Mississippi Salt basin, extends for about 55 mi north-northwest-south-southeast from Jasper County to Greene County, Mississippi. Heidelberg, Sandersville, Choctaw, Pool Creek, North Wausau, Wausau, Thompson Creek, South Thompson Creek, Flat Branch, North Sand Hill, and Avera oil fields are situated along the graben (from north to south). Cumulative oil production is about 170 million bbl, with about 83% from Heidelberg field. Eutaw and Tuscaloosa sandstones are the chief reservoirs. Structure contour maps and structure cross sections perpendicular to the trend of the graben have been used to define the character of the system. The graben is superimposed on a Louann Salt ridge and associated piercement domes. The location of the salt ridge may be controlled by faulting of the pre-Louann basement (Phillips fault system). Most hydrocarbons are found in upthrown fault closure along either the eastern or western bounding faults. Downthrown Selma chalk, Mooringsport shales, or other impermeable units provide the seal. Minor amounts of oil occur within the graben, either in fault closure or faulted anticlinal closure formed by salt uplift or simultaneous rollover into the principal bounding faults.

  18. Monologue or Dialogue? Stepping Away from the Abyss in Higher Education

    ERIC Educational Resources Information Center

    Stern, Julian

    2009-01-01

    This paper investigates the possibilities of the use of dialogue, and the dangers of the use of monologue, in higher education in the early twenty-first century, in a period facing a number of smaller- and larger-scale crises--each interpreted as an "abyss" of some kind. How does higher education contribute, positively or negatively, to personal…

  19. Long-term change in the abyssal NE Atlantic: The ‘Amperima Event’ revisited

    NASA Astrophysics Data System (ADS)

    Billett, D. S. M.; Bett, B. J.; Reid, W. D. K.; Boorman, B.; Priede, I. G.

    2010-08-01

    The results from a time series study (1989-2005) at a depth of 4850 m on the Porcupine Abyssal Plain, NE Atlantic, are presented, showing radical changes in the density of large invertebrates (megafauna) over time. Major changes occurred in a number of different taxa between 1996 and 1999 and then again in 2002. One species of holothurian, Amperima rosea, was particularly important, increasing in density by over three orders of magnitude. There were no significant changes in total megafaunal biomass during the same period. Peaks in density were correlated to reductions in mean body size, indicating that the increases were related to large-scale recruitment events. The changes occurred over a wide area of the Porcupine Abyssal Plain. Comparisons made with changes in the density of protozoan and metazoan meiofauna, and with macrofauna, showed that major changes in community structure occurred in all size fractions of the benthic community at the same time. This suggests that the faunal changes were driven by environmental factors rather than being stochastic population imbalances of one or two species. Large-scale changes in the flux of organic matter to the abyssal seafloor have been noted in the time series, particularly in 2001, and may be related to the sudden mass occurrence of A. rosea the following year. Time-varying environmental factors are important in influencing the occurrence of megafauna on the abyssal seafloor.

  20. Fault diagnosis

    NASA Technical Reports Server (NTRS)

    Abbott, Kathy

    1990-01-01

    The objective of the research in this area of fault management is to develop and implement a decision aiding concept for diagnosing faults, especially faults which are difficult for pilots to identify, and to develop methods for presenting the diagnosis information to the flight crew in a timely and comprehensible manner. The requirements for the diagnosis concept were identified by interviewing pilots, analyzing actual incident and accident cases, and examining psychology literature on how humans perform diagnosis. The diagnosis decision aiding concept developed based on those requirements takes abnormal sensor readings as input, as identified by a fault monitor. Based on these abnormal sensor readings, the diagnosis concept identifies the cause or source of the fault and all components affected by the fault. This concept was implemented for diagnosis of aircraft propulsion and hydraulic subsystems in a computer program called Draphys (Diagnostic Reasoning About Physical Systems). Draphys is unique in two important ways. First, it uses models of both functional and physical relationships in the subsystems. Using both models enables the diagnostic reasoning to identify the fault propagation as the faulted system continues to operate, and to diagnose physical damage. Draphys also reasons about behavior of the faulted system over time, to eliminate possibilities as more information becomes available, and to update the system status as more components are affected by the fault. The crew interface research is examining display issues associated with presenting diagnosis information to the flight crew. One study examined issues for presenting system status information. One lesson learned from that study was that pilots found fault situations to be more complex if they involved multiple subsystems. Another was pilots could identify the faulted systems more quickly if the system status was presented in pictorial or text format. Another study is currently under way to

  1. Stratigraphic Relationships on Husband Hill, Mars

    NASA Astrophysics Data System (ADS)

    Cole, S. B.; Watters, W. A.; Squyres, S. W.

    2011-03-01

    We measure bedding plane orientations of outcrops on Cumberland Ridge in the Columbia Hills. Our measurements are consistent with the hypotheses that the outcrops (1) form a stratigraphic section, and (2) drape the Husband Hill edifice.

  2. Chronology of polyphase extension in the Windermere Hills, northeast Nevada

    USGS Publications Warehouse

    Mueller, K.J.; Cerveny, P.K.; Perkins, M.E.; Snee, L.W.

    1999-01-01

    Fission-track and 40Ar/39Ar dating and chemical correlation of volcanic strata exposed in the Windermere Hills and northern Pequop Mountains, northeast Nevada, indicate a protracted, polyphase history of Tertiary (late Eocene-late Miocene) extension along the northern margin of a major Cordilleran metamorphic core complex. Early extension is recorded by a west-tilted half graben filled with early Oligocene (34.79 ?? 0.18-39.18 ?? 0.12 Ma) sedimentary rocks in the eastern Windermere Hills above the low-angle Black Mountain detachment fault. The early Oligocene half graben conformably overlies a widespread suite of late Eocene (39.18 ?? 0.12-40.38 ?? 0.06 Ma) calc-alkaline volcanic rocks, reflecting a temporal link between early extension at a high structural level and the end of the ignimbrite flare-up. These strata are cut by east-west-striking normal faults, which are exposed along, and parallel to, the northern margin of the metamorphic complex. Available age data (e.g., between 14.93 ?? 0.08 and 34.79 ?? 0.18 Ma) permit the interpretation that the east-west-striking faults formed at the same time as, or after, large-magnitude unroofing of high-grade rocks. We interpret the east-west-striking faults to accommodate differential uplift of greenschist-grade metamorphic rocks in the upper crust, above a lateral ramp in a west-northwest-directed mylonitic shear zone. Subsequent extension in the Windermere Hills is defined by deep, rapidly filled half grabens of middle Miocene (<7.42 ?? 2.0 to 14.93 ?? 0.08 Ma) age that unconformably overlie older faults and synextensional deposits. These are the youngest half grabens in the region and are inferred to be initiated by extensional stresses imparted to the base of the lithosphere by a laterally spreading mantle plume (e.g., the Yellowstone hotspot) located in southeastern Oregon at this time.

  3. Strike-parallel variations in clay minerals and fault vergence in the Cascadia subduction zone

    NASA Astrophysics Data System (ADS)

    Underwood, Michael B.

    2002-02-01

    Clay minerals probably affect the zonation of mechanical properties within a thick unit of abyssal-plain deposits as they enter the Cascadia subduction zone. Landward- vergent thrust faults develop above a deeper décollement because smectite-rich mudrocks within that corridor release more water during clay dehydration, which in turn elevates pore pressure and reduces basal shear stress relative to wedge strength. Conversely, dilution of smectite by illite and chlorite increases the frictional coefficient, and fluid overpressure should drop where smectite dehydration is volumetrically reduced. Thus, thrust faults within chlorite-rich segments of the margin are seaward vergent.

  4. Abundance, diversity, and latitudinal gradients of southeastern Atlantic and Antarctic abyssal gastropods

    NASA Astrophysics Data System (ADS)

    Schrödl, M.; Bohn, J. M.; Brenke, N.; Rolán, E.; Schwabe, E.

    2011-03-01

    Mollusca are widely used for deriving concepts on deep-sea biology and biodiversity, yet abyssal collections are limited to only a few regions of the world ocean and biased toward the northern Atlantic. The present study compares gastropod molluscs sampled along a transect through the southern Atlantic from the equator to Antarctica. The DIVA I and II expeditions concentrated on the hardly explored Guinea, Angola, and Cape Basins. Of the 145 deep-sea deployments (5025-5656 m depth) analyzed to date, 20 have yielded 68 specimens of benthic gastropods, representing 27 species. Only five abyssal species were previously known, four of them from the northern Atlantic deep sea; the remainder appear to be undescribed. Interestingly, there is no faunal overlap with the nearby Antarctic deep-sea. Most of these DIVA species (63%) are represented by single individuals, or limited to one or two stations. The rarity (i.e. 0.55 specimens m -2 calculated from quantitative corers) and still undetectable patchiness of southeastern Atlantic abyssal gastropods may indicate "source-sink" dynamics, but comparison is needed with thus far hardly explored regional bathyal faunas. The BRENKE-epibenthic sledge (EBS) may be efficient at surveying the abyssal gastropod species richness, but is shown to drastically underestimate true abundances. Low diversity values throughout the three southern Atlantic ocean basins do further challenge earlier estimates of a hyperdiverse global abyssal macrofauna. Comparative EBS data available from the southern hemisphere indicate a gradient from the equatorial Guinea Basin towards higher gastropod abundances and diversity in Antarctica. This is in clear contrast to the paradigm of a globally strongly decreasing marine diversity from lower to higher latitudes, highlighting the importance of further exploring the southern fauna from the tropics to Antarctica.

  5. 27 CFR 9.193 - Rattlesnake Hills.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Valley viticultural area (27 CFR 9.69). From the beginning point, the Rattlesnake Hills viticultural area... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Rattlesnake Hills. 9.193... Rattlesnake Hills. (a) Name. The name of the viticultural area described in this section is “Rattlesnake...

  6. 27 CFR 9.193 - Rattlesnake Hills.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Valley viticultural area (27 CFR 9.69). From the beginning point, the Rattlesnake Hills viticultural area... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Rattlesnake Hills. 9.193... Rattlesnake Hills. (a) Name. The name of the viticultural area described in this section is “Rattlesnake...

  7. 27 CFR 9.193 - Rattlesnake Hills.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Valley viticultural area (27 CFR 9.69). From the beginning point, the Rattlesnake Hills viticultural area... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Rattlesnake Hills. 9.193... Rattlesnake Hills. (a) Name. The name of the viticultural area described in this section is “Rattlesnake...

  8. 27 CFR 9.52 - Chalk Hill.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Chalk Hill. 9.52 Section 9... TREASURY ALCOHOL AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.52 Chalk Hill. (a) Name. The name of the viticultural area described in this section is “Chalk Hill.” (b) Approved...

  9. 27 CFR 9.52 - Chalk Hill.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Chalk Hill. 9.52 Section 9... TREASURY ALCOHOL AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.52 Chalk Hill. (a) Name. The name of the viticultural area described in this section is “Chalk Hill.” (b) Approved...

  10. 27 CFR 9.52 - Chalk Hill.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Chalk Hill. 9.52 Section 9... TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.52 Chalk Hill. (a) Name. The name of the viticultural area described in this section is “Chalk Hill.” (b) Approved...

  11. 27 CFR 9.52 - Chalk Hill.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Chalk Hill. 9.52 Section 9... TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.52 Chalk Hill. (a) Name. The name of the viticultural area described in this section is “Chalk Hill.” (b) Approved...

  12. 27 CFR 9.52 - Chalk Hill.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Chalk Hill. 9.52 Section 9... TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.52 Chalk Hill. (a) Name. The name of the viticultural area described in this section is “Chalk Hill.” (b) Approved...

  13. Fault mechanics

    SciTech Connect

    Segall, P. )

    1991-01-01

    Recent observational, experimental, and theoretical modeling studies of fault mechanics are discussed in a critical review of U.S. research from the period 1987-1990. Topics examined include interseismic strain accumulation, coseismic deformation, postseismic deformation, and the earthquake cycle; long-term deformation; fault friction and the instability mechanism; pore pressure and normal stress effects; instability models; strain measurements prior to earthquakes; stochastic modeling of earthquakes; and deep-focus earthquakes. Maps, graphs, and a comprehensive bibliography are provided. 220 refs.

  14. Progressive deformation and degradation along the northern portion of the Big Bend of the San Andreas Fault

    SciTech Connect

    Arrowsmith, R. . Dept. of Geology)

    1992-01-01

    The 1-to-5-km-wide Elkhorn Hills in the southeastern Carrizo Plain, California (bounded by the San Andreas Fault (SAF) on the southwest and a series of reverse faults on the northeast), are progressively deformed as they are displaced along the SAF into the northern portion of the Big Bend. The structural development follows this sequence: (1) an alluvial fan surface is cut by reverse faults about 500 m northeast of the SAF, and grabens form in the foot-wall block of the faults; (2) a reverse fault striking 25 degrees counterclockwise from the SAF cuts the fan surface 2 to 3 km northeast of the SAF, left-stepping grabens form in the reverse fault hanging wall; their orientation is controlled by distributed SAF parallel shear and by dip variations in the reverse fault surface; (3) reverse faults accumulate displacement, increasing relief in the Elkhorn Hills, while hanging wall extension decreases; (4) slip on deeper thrusts accommodates contraction within the Big Bend, and Elkhorn Hills deformation decreases. Within the Northern Elkhorn Hills, the evidence for the development of deformation in time and space includes a southeastward increase in total displacement on the normal and reverse faults, a southeastward increase in the degradation of the normal fault scarps, and the beheading of a southwest flowing drainage by slip on the reverse fault, as well as cutting of that drainage by normal faults, implying contemporaneous propagation of normal and reverse faults. Based on a ground pattern age of 4 to 10 ka for the beheaded drainage and the present location of the reverse fault, a propagation rate of 3.5 to 10 cm/yr is calculated: consistent with the 3.5 cm/yr at which the Elkhorn Hills are displaced into the Big Bend by strike-slip motion along the SAF.

  15. Style of faults and associated fractures in Austin Chalk: northern extension of balcones fault zone, central Texas

    SciTech Connect

    Reaser, D.F.; Collins, E.W.

    1988-09-01

    Distributions, geometries, and densities of faults and associated fractures in the Cretaceous Austin Chalk were studied in outcrop within the northernmost extension of the Balcones fault zone in Ellis and northern Hill Counties, Texas. Description of the fracture systems may be applicable to hydrocarbon exploration and production from this unit and to locating the proposed Dallas-Fort Worth Area Superconducting Super Collider site in Ellis County.

  16. Geologic character of fault geometry and deformation of the Wildcat Fault, Berkeley, California

    NASA Astrophysics Data System (ADS)

    Onishi, C. T.; Karasaki, K.; Goto, J.; Moriya, T.; Ueta, K.; Tanaka, S.; Hamada, T.; Ito, H.; Tsukuda, K.

    2010-12-01

    In our analog study of fault hydrology, we use an interdisciplinary approach to investigate fault geology and its effects on regional hydrology. The study area is along the Wildcat Fault, a right-lateral strike-slip fault that is a splay of the Hayward Fault, which extends along the west side of the Berkeley Hills, California. Geologic mapping suggests that the Wildcat Fault here mainly separates the Miocene Claremont Formation composed of shale and cherts, and the Miocene-Pliocene Orinda Formation/San Pablo Group, composed of conglomerate, sandstone, and siltstone. We excavated several trenches to expose bedrock; we acquired seismic reflection and electrical resistivity data and three vertical boreholes and one inclined borehole cored across the Wildcat Fault. Trenching and coring indicate that the geology is more complex than the surface mapping indicates, especially along the contact between the Claremont Formation and Orinda Formation/San Pablo Group. In trench exposures, we mapped several zones of fault gouge that marked the contact between chert and siltstone, sandstone and siltstone, and chert and chert. At depths <150 m subsurface, we saw more than thirty zones of breccia and gouge, and two zones of cataclasite. Cores from vertical boring show a lithological dominance of Claremont Formation. We suggest that the Wildcat Fault in this area contains multiple shear zones in a zone of deformation at least 150 m wide. We have built a 3D geologic model to show the geometry of fault strands associated with the Wildcat Fault. The influence of fault gouge, breccia and cataclasite on the hydrology of the Wildcat Fault zone, slug, injection, and pumping tests in boreholes are reported by Karasaki et al. in a companion paper.

  17. Modeling the Dynamic Rupture Process of the 1987 Superstition Hills Earthquake

    NASA Astrophysics Data System (ADS)

    Liu, Q.; Archuleta, R. J.

    2012-12-01

    The Mw 6.6 Superstition Hill (SH) earthquake (Nov. 24, 1987) in southern California intrigues us in terms of its rupture dynamics. Kinematic source inversion results imply a complex event, which consisted of 3 subevents (Frankel & Wennerberg, 1989; Wald et al., 1990). All of the subevents seemed to initiate at the northwestern end of the SH fault where SH fault intersects with a conjugate Elmore Ranch (ER) fault. Moreover a Mw 6.2 earthquake and its aftershock sequence occurred on the Elmore Ranch fault within the 12 hours before the SH earthquake. Existing studies show that the distribution of seismicity correlates with the subsurface geology (Fuis et al. 1984). Based on comparison of the extent of each subevent with the fault trace, the fault geometry might make significant contribution to the dynamic process. The San-Jacinto (SJ) fault system certainly complicates the local stress field near SH fault by introducing several pairs of conjugate faults at various length scales in the region. A possible scenario of the Mw 6.6 event would be a sequence of seismic events on the conjugate ER fault perturbed the already complicated initial stress field on the non-planar SH fault and triggered the SH event. Using a finite element approach (Ma & Liu, 2006), we try to create a reasonable initial stress condition for the Mw 6.6 event and model its rupture process, incorporating complex fault geometry, 3D velocity structure and varying frictional properties (velocity weakening/strengthening) both along strike and dip. Recent results on SH fault's creeping behavior (e.g., Wei et al. 2009) also impose constraints on its frictional and rheological material properties, which is essential in the dynamic rupture modeling as well as the nucleation phase.

  18. New insights into the abyssal sponge fauna of the Kurile-Kamchatka plain and Trench region (Northwest Pacific)

    NASA Astrophysics Data System (ADS)

    Downey, Rachel V.; Janussen, Dorte

    2015-01-01

    The under-explored abyssal depths of the Kurile-Kamchatka region have been re-examined during the KuramBio (Kurile-Kamchatka Biodiversity Study) expedition. Combining new KuramBio data with previous expedition data in this region has enhanced our understanding abyssal sponge fauna, in particular, the patchiness, rarity, and exceptional richness of the Cladorhizidae family. In total, 14 sponge species, from 7 genera, in 5 families, within two classes (Demospongiae and Hexactinellida) were collected. Of the 14 species, 29% (4 spp.) have been found previously in this region, 36% (5 spp.) were new to the regional abyssal fauna, and 21% (3 spp.) were new to science. The number of abyssal species in this region has now been increased by 26% (8 spp.) and genera by nearly 15% (2 genera). Rarity is a prominent feature of this abyssal fauna, with more than half of species only found at one station, and 83% (19 spp.) of species found previously in this region were not re-found during KuramBio. Cladorhizid sponges dominate demosponge species and genera richness in the abyssal Kurile-Kamchatka region; accounting for 87% (20 spp.) of all demosponge species, and accounting for over 60% (5 genera) of all demosponge genera. Sponge richness in this region is potentially aided by the productivity of the ocean waters, the geological age of the Pacific Ocean, low population densities, and the varied topographic features (ridges, trenches, and seamounts) found in this region. Unusually, the dominance of demosponges in the Kurile-Kamchatka sponge faunal composition is not replicated in other well-sampled abyssal regions, which tend to be richer in deep-sea hexactinellid fauna. Broad depth, latitudinal and longitudinal ranges in Kurile-Kamchatka abyssal fauna are a key characteristic of this faunal assemblage. Strong abyssal faunal connectivity is found between the Kurile-Kamchatka region and North Pacific abyssal fauna, with weaker faunal connections found with the adjacent semi

  19. SRTM Anaglyph: Haro and Kas Hills

    NASA Technical Reports Server (NTRS)

    2001-01-01

    On January 26, 2001 the Kachchh region in western India suffered the most deadly earthquake in India's history. This three-dimensional view of landforms northeast of the city of Bhuj depicts geologic structures that are of interest in the study the tectonic processes that may have led to that earthquake. However, preliminary field studies indicate that these structures are composed of Mesozoic rocks that are overlain by younger rocks showing little deformation. Thus these structures may be old, not actively growing, and not directly related to the recent earthquake.

    The Haro Hills are on the left and the Kas Hills are on the right. The Haro Hills are an 'anticline,' which is an upwardly convex elongated fold of layered rocks. The anticline is distinctly ringed by an erosion resistant layer of sandstone. The east-west orientation of the anticline may relate to the crustal compression that has occurred during India's northward movement toward, and collision with, Asia. In contrast, the largest of the Kas Hills appears to be a tilted (to the south) and faulted (on the north) block of layered rocks. Also seen here, the curvilinear ridge trending toward the southwest from the image center is an erosion resistant 'dike,' which is an igneous intrusion into older 'host' rocks along a fault plane or other crack. The dike also appears to extend northeast from the image center as a dark line having very little topography. Its location between the tilted block and a smaller anticline to the north (directly east of the larger anticline) probably indicates that the dike fills the fault that separates these contrasting geologic structures. These features are simple examples of how digital elevation data can stereoscopically enhance satellite imagery to provide a direct input to geologic studies.

    The stereoscopic effect of this anaglyph was created by first draping a Landsat satellite image (taken just two weeks after the earthquake) over preliminary digital elevation

  20. Rocks of the Columbia Hills

    USGS Publications Warehouse

    Squyres, S. W.; Arvidson, R. E.; Blaney, D.L.; Clark, B. C.; Crumpler, L.; Farrand, W. H.; Gorevan, S.; Herkenhoff, K. E.; Hurowitz, J.; Kusack, A.; McSween, H.Y.; Ming, D. W.; Morris, R.V.; Ruff, S.W.; Wang, A.; Yen, A.

    2006-01-01

    The Mars Exploration Rover Spirit has identified five distinct rock types in the Columbia Hills of Gusev crater. Clovis Class rock is a poorly sorted clastic rock that has undergone substantial aqueous alteration. We interpret it to be aqueously altered ejecta deposits formed by impacts into basaltic materials. Wishstone Class rock is also a poorly sorted clastic rock that has a distinctive chemical composition that is high in Ti and P and low in Cr. Wishstone Class rock may be pyroclastic or impact in origin. Peace Class rock is a sedimentary material composed of ultramafic sand grains cemented by significant quantities of Mg- and Ca-sulfates. Peace Class rock may have formed when water briefly saturated the ultramafic sands and evaporated to allow precipitation of the sulfates. Watchtower Class rocks are similar chemically to Wishstone Class rocks and have undergone widely varying degrees of near-isochemical aqueous alteration. They may also be ejecta deposits, formed by impacts into Wishstone-rich materials and altered by small amounts of water. Backstay Class rocks are basalt/trachybasalt lavas that were emplaced in the Columbia Hills after the other rock classes were, either as impact ejecta or by localized volcanic activity. The geologic record preserved in the rocks of the Columbia Hills reveals a period very early in Martian history in which volcanic materials were widespread, impact was a dominant process, and water was commonly present. Copyright 2006 by the American Geophysical Union.

  1. Slip on faults in the Imperial Valley triggered by the 4 April 2010 Mw 7.2 El Mayor-Cucapah earthquake revealed by InSAR

    NASA Astrophysics Data System (ADS)

    Wei, Meng; Sandwell, David; Fialko, Yuri; Bilham, Roger

    2011-01-01

    Radar interferometry (InSAR), field measurements and creepmeters reveal surface slip on multiple faults in the Imperial Valley triggered by the main shock of the 4 April 2010 El Mayor-Cucapah Mw 7.2 earthquake. Co-seismic offsets occurred on the San Andreas, Superstition Hills, Imperial, Elmore Ranch, Wienert, Coyote Creek, Elsinore, Yuha, and several minor faults near the town of Ocotillo at the northern end of the mainshock rupture. We documented right-lateral slip (<40 mm) on northwest-striking faults and left-lateral slip (<40 mm) on southwest-striking faults. Slip occurred on 15-km- and 20-km-long segments of the San Andreas Fault in the Mecca Hills (≤50 mm) and Durmid Hill (≤10 mm) respectively, and on 25 km of the Superstition Hills Fault (≤37 mm). Field measurements of slip on the Superstition Hills Fault agree with InSAR and creepmeter measurements to within a few millimeters. Dislocation models of the InSAR data from the Superstition Hills Fault confirm that creep in this sequence, as in previous slip events, is confined to shallow depths (<3 km).

  2. Study of Reservoir Heterogencities and Structural Features Affecting Production in the Shallow Oil Zone, Eastern Elk Hills Area, California

    SciTech Connect

    Janice Gillespie

    2004-11-01

    Late Neogene (Plio-Pleistocene) shallow marine strata of the western Bakersfield Arch and Elk Hills produce hydrocarbons from several different reservoirs. This project focuses on the shallow marine deposits of the Gusher and Calitroleum reservoirs in the Lower Shallow Oil Zone (LSOZ). In the eastern part of the study area on the Bakersfield Arch at North and South Coles Levee field and in two wells in easternmost Elk Hills, the LSOZ reservoirs produce dry (predominantly methane) gas. In structurally higher locations in western Elk Hills, the LSOZ produces oil and associated gas. Gas analyses show that gas from the eastern LSOZ is bacterial and formed in place in the reservoirs, whereas gas associated with oil in the western part of the study area is thermogenic and migrated into the sands from deeper in the basin. Regional mapping shows that the gas-bearing LSOZ sands in the Coles Levee and easternmost Elk Hills area are sourced from the Sierra Nevada to the east whereas the oil-bearing sands in western Elk Hills appear to be sourced from the west. The eastern Elk Hills area occupied the basin depocenter, farthest from either source area. As a result, it collected mainly low-permeability offshore shale deposits. This sand-poor depocenter provides an effective barrier to the updip migration of gases from east to west. The role of small, listric normal faults as migration barriers is more ambiguous. Because our gas analyses show that the gas in the eastern LSOZ reservoirs is bacterial, it likely formed in-place near the reservoirs and did not have to migrate far. Therefore, the gas could have been generated after faulting and accumulated within the fault blocks as localized pools. However, bacterial gas is present in both the eastern AND western parts of Elk Hills in the Dry Gas Zone (DGZ) near the top of the stratigraphic section even though the measured fault displacement is greatest in this zone. Bacterial gas is not present in the west in the deeper LSOZ which

  3. Conversion of the Big Hill geological site characterization report to a three-dimensional model.

    SciTech Connect

    Stein, Joshua S.; Rautman, Christopher Arthur

    2003-02-01

    The Big Hill salt dome, located in southeastern Texas, is home to one of four underground oil-storage facilities managed by the U. S. Department of Energy Strategic Petroleum Reserve (SPR) Program. Sandia National Laboratories, as the geotechnical advisor to the SPR, conducts site-characterization investigations and other longer-term geotechnical and engineering studies in support of the program. This report describes the conversion of two-dimensional geologic interpretations of the Big Hill site into three-dimensional geologic models. The new models include the geometry of the salt dome, the surrounding sedimentary units, mapped faults, and the 14 oil storage caverns at the site. This work provides a realistic and internally consistent geologic model of the Big Hill site that can be used in support of future work.

  4. Latitudinal variation in invertebrate megafaunal abundance and biomass in the North Atlantic Ocean Abyss

    NASA Astrophysics Data System (ADS)

    Thurston, M. H.; Rice, A. L.; Bett, B. J.

    1998-01-01

    Megafauna was collected by otter trawl at two widely separated abyssal sites in the eastern North Atlantic Ocean. The northern site, on the Porcupine Abyssal Plain (PAP, 4850 m), is subject to strong seasonal pulses of phytodetritus deposition, whereas the southern site, on the Madeira Abyssal Plain (OLIGO, 4500-4650 m), showed no indication of such deposition. Data from these two sites were compared with those from a third site (GME), also apparently not affected by phytodetritus, but on the Madeira Abyssal Plain 1200 km from OLIGO. Mean abundance and biomass of invertebrate megafauna at PAP were 72.6 individuals ha -1 and 1974 g ha -1 respectively. The corresponding values for OLIGO were 10.2 individuals ha -1 and 63.4 g ha -1 and for GME 21.7 individuals ha -1 and 112.9 g ha -1. Size-spectral curves of abundance and biomass based on PAP samples showed peaks in the 40-80 g wet weight class, thus confirming the megafauna as a functional entity. No evidence for seasonal variation of abundance or biomass was found. At OLIGO, abundance declined more or less regularly over the organism size range sampled, and biomass was spread fairly evenly across the larger size classes. Major differences in trophic structure among the three sites were evident, with OLIGO and GME more similar to one another than either were to PAP, with much of the higher biomass at PAP represented by particle-selective detritivorous holothurians. The contribution of invertebrates to overall megafaunal biomass at OLIGO (8%) and GME (30%) was lower than at PAP (48%), but a high proportion of fish biomass at OLIGO and GME, and almost all at PAP, belonged to macrophagous species trophically independent of benthic production.

  5. Species composition and distribution of bivalves in bathyal and abyssal depths of the Sea of Japan

    NASA Astrophysics Data System (ADS)

    Kamenev, Gennady M.

    2013-02-01

    Twenty-six bivalve species collected by four Russian (1972, 1976, 1985, 2005) and Russian-German (2010) expeditions in the bathyal and abyssal depths of the Sea of Japan (465-3435 m) are listed with the material examined and illustrated. Taxonomic decisions herein: Robaia habei Scarlato, 1981 is synonymized with Nuculana (Robaia) robai (Kuroda, 1929); following Scarlato (1981) and Coan et al. (2000)Dacrydium nipponicum Okutani, 1975 and Dacrydium minimum Okutani and Izumidate, 1992 are synonymized with Dacrydium vitreum (Möller, 1842); Maorithyas yamatotaensis Okutani and Izumidate, 1992 is synonymized with Adontorhina cyclia Berry, 1947; Axinopsida rubiginosa Okutani and Izumidate, 1992 is synonymized with Mendicula ferruginosa (Forbes, 1844); Cardiomya lindbergi batialis Scarlato, 1972 is synonymized with Cardiomya tosaensis (Kuroda, 1948); Cuspidaria sadoensis Okutani and Ito, 1983 is synonymized with Cuspidaria ascoldica Scarlato, 1972; Cyclocardia rjabininae (Scarlato, 1955) recognized as valid and distinct from Cyclocardia ovata (Rjabinina, 1952). The deep-water bivalve fauna of the Sea of Japan is characterized by an impoverished shelf fauna and consists of eurybathic species that extend from the shelf to the bathyal and abyssal zones. Most of them have a wide geographic distribution and inhabit cold water regions of the Northern Atlantic, Northern Pacific, and Arctic Ocean. Only five species are endemic to the Sea of Japan. With increase in depth, the species richness of bivalves decreases. In the depth range from 200 to 1600 m, all species (26) found in the deep Sea of Japan were recorded, while only 10 species were recorded in the lower bathyal slope (1700-3000 m). At depths below 3000 m, only D. vitreum, Delectopecten vancouverensis (Whiteaves, 1893), and Thyasira (Parathyasira) sp. were found. The lack of typical abyssal species of bivalves in the deep Sea of Japan is probably connected with the isolation of this body of water from the Pacific abyssal

  6. The SCEC 3D Community Fault Model (CFM-v5): An updated and expanded fault set of oblique crustal deformation and complex fault interaction for southern California

    NASA Astrophysics Data System (ADS)

    Nicholson, C.; Plesch, A.; Sorlien, C. C.; Shaw, J. H.; Hauksson, E.

    2014-12-01

    Southern California represents an ideal natural laboratory to investigate oblique deformation in 3D owing to its comprehensive datasets, complex tectonic history, evolving components of oblique slip, and continued crustal rotations about horizontal and vertical axes. As the SCEC Community Fault Model (CFM) aims to accurately reflect this 3D deformation, we present the results of an extensive update to the model by using primarily detailed fault trace, seismic reflection, relocated hypocenter and focal mechanism nodal plane data to generate improved, more realistic digital 3D fault surfaces. The results document a wide variety of oblique strain accommodation, including various aspects of strain partitioning and fault-related folding, sets of both high-angle and low-angle faults that mutually interact, significant non-planar, multi-stranded faults with variable dip along strike and with depth, and active mid-crustal detachments. In places, closely-spaced fault strands or fault systems can remain surprisingly subparallel to seismogenic depths, while in other areas, major strike-slip to oblique-slip faults can merge, such as the S-dipping Arroyo Parida-Mission Ridge and Santa Ynez faults with the N-dipping North Channel-Pitas Point-Red Mountain fault system, or diverge with depth. Examples of the latter include the steep-to-west-dipping Laguna Salada-Indiviso faults with the steep-to-east-dipping Sierra Cucapah faults, and the steep southern San Andreas fault with the adjacent NE-dipping Mecca Hills-Hidden Springs fault system. In addition, overprinting by steep predominantly strike-slip faulting can segment which parts of intersecting inherited low-angle faults are reactivated, or result in mutual cross-cutting relationships. The updated CFM 3D fault surfaces thus help characterize a more complex pattern of fault interactions at depth between various fault sets and linked fault systems, and a more complex fault geometry than typically inferred or expected from

  7. Demographic indicators of change in a deposit-feeding abyssal holothurian community (Station M, 4000 m)

    NASA Astrophysics Data System (ADS)

    Huffard, Christine L.; Kuhnz, Linda A.; Lemon, Larissa; Sherman, Alana D.; Smith, Kenneth L.

    2016-03-01

    Holothurians are among the most abundant benthic megafauna at abyssal depths, and important consumers and bioturbators of organic carbon on the sea floor. Significant fluctuations in abyssal holothurian density are often attributed to species-specific responses to variable particulate organic carbon flux (food supply) stemming from surface ocean events. We report changes in densities of 19 holothurian species at the abyssal monitoring site Station M in the northeast Pacific, recorded during 11 remotely operated vehicle surveys between Dec 2006 and Oct 2014. Body size demographics are presented for Abyssocucumis abyssorum, Synallactidae sp. 1, Paelopatides confundens, Elpidia sp. A, Peniagone gracilis, Peniagone papillata, Peniagone vitrea, Peniagone sp. A, Peniagone sp. 1, and Scotoplanes globosa. Densities were lower and species evenness was higher from 2006-2009 compared to 2011-2014. Food supply of freshly-settled phytodetritus was exceptionally high during this latter period. Based on relationships between median body length and density, numerous immigration and juvenile recruitment events of multiple species appeared to take place between 2011 and 2014. These patterns were dominated by elpidiids (Holothuroidea: Elasipodida: Elpidiidae), which consistently increased in density during a period of high food availability, while other groups showed inconsistent responses. We considered minimum body length to be a proxy for size at juvenile recruitment. Patterns in density clustered by this measure, which was a stronger predictor of maximum density than median and mean body length.

  8. Abyssal Scavenging Communities attracted to Sargassum and fish in the Sargasso Sea

    NASA Astrophysics Data System (ADS)

    Fleury, Aharon G.; Drazen, Jeffrey C.

    2013-02-01

    Deep-sea communities rely on epipelagic surface production as a primary source of energy and food. The flux of phytodetritus drives many abyssal ecological processes but the flux of large particles such as nekton carcasses, macroalgae, and wood may also be important. Recent baited camera experiments noted that some abyssal fish consumed spinach and phytoplankton placed on the seafloor. To evaluate if fish or other scavengers would consume natural plant or macroalgal material falling to the deep-sea floor we conducted camera experiments using Sargassum or mackerel bait in the Sargasso Sea. A benthic community of invertebrates was attracted to Sargassum, which naturally falls to the seafloor in this area. In five instances it was observed that an isopod Bathyopsurus sp. removed a piece of Sargassum from the main clump and left the field of view with it. An ophiuroid is also observed handling a piece of Sargassum. The group of scavengers attracted to mackerel bait was very different and was dominated by large ophidiid fish. In contrast to studies elsewhere in the abyssal North Atlantic, only a small number of rattails are observed, which could be related to water depth or an ichthyofaunal zonal change between oligotrophic and eutrophic regions.

  9. Long-term change in the megabenthos of the Porcupine Abyssal Plain (NE Atlantic)

    NASA Astrophysics Data System (ADS)

    Billett, D. S. M.; Bett, B. J.; Rice, A. L.; Thurston, M. H.; Galéron, J.; Sibuet, M.; Wolff, G. A.

    A radical change in the abundance of invertebrate megafauna on the Porcupine Abyssal Plain is reported over a period of 10 years (1989-1999). Actiniarians, annelids, pycnogonids, tunicates, ophiuroids and holothurians increased significantly in abundance. However, there was no significant change in wet weight biomass. Two holothurian species, Amperima rosea and Ellipinion molle, increased in abundance by more than two orders of magnitude. Samples from the Porcupine Abyssal Plain over a longer period (1977-1999) show that prior to 1996 these holothurian species were always a minor component of the megafauna. From 1996 to 1999 A. rosea was abundant over a wide area of the Porcupine Abyssal Plain indicating that the phenomenon was not a localised event. Several dominant holothurian species show a distinct trend in decreasing body size over the study period. The changes in megafauna abundance may be related to environmental forcing (food supply) rather than to localised stochastic population variations. Inter-annual variability and long-term trends in organic matter supply to the seabed may be responsible for the observed changes in abundance, species dominance and size distributions.

  10. Morphological, histochemical and immunohistochemical study of the gill epithelium in the abyssal teleost fish Coelorhynchus coelorhynchus.

    PubMed

    Calabrò, Concetta; Albanese, Maria Pia; Lauriano, Eugenia Rita; Martella, Silvestro; Licata, Aurelio

    2005-01-01

    Histochemical and immunohistochemical study was carried out on nitrinergic innervation and neuroendocrine system in the gill epithelium of the abyssal fish Coelorhynchus coelorhynchus. The results showed that nNOS-positive nerve fibers, originating from the branchial arch were present in the subepithelial tissue of branchial primary filament. nNOS-positive neuroendocrine cells were also present in the primary filaments and secondary lamellae. Numerous mucous cells in the gill epithelium were AB/PAS-positive, while sialic acid was absent as confirmed by neuraminidase reaction and WGA lectin histochemistry. The mucus compounds in abyssal teleost fish are different from those found in pelagic species, being related to their living conditions. In abyssal species, greater numbers of chloride and neuroendocrine cells are involved in the movement of water and electrolytes. Neuroendocrine cells possess oxygen receptors which mediate the cardiovascular and ventilatory response to oxygen deficiency, as reported in teleost species. Besides, NO contributes through nervous stimulation to the regulation of vascular tone and blood circulation in the gill. PMID:15871563

  11. GLORIA side-scan imagery of Aleutian basin, Bering Sea slope and Abyssal plain

    SciTech Connect

    Carlson, P.R.; Cooper, A.K.; Gardner, J.V.; Karl, H.A.; Marlow, M.S.; Stevenson, A.J.; Huggett, Q.; Kenyon, N.; Parson, L.

    1987-05-01

    During July-September 1986, about 700,000 km/sup 2/ of continental slope and abyssal plain of the Aleutian basin, Bering Sea, were insonified with GLORIA (Geological Long Range Inclined Asdic) side-scane sonar. A sonar mosaic displays prominent geomorphic features including the massive submarine canyons of the Beringian and the northern Aleutian Ridge slopes and shows well-defined sediment patterns including large deep-sea channels and fan systems on the Aleutian basin abyssal plain. Dominant erosional and sediment transport processes on both the Beringian and the Aleutian Ridge slopes include varieties of mass movement that range from small debris flows and slides to massive slides and slumps of blocks measuring kilometers in dimension. Sediment-flow patterns that appear to be formed by sheet flow rather than channelized flow extend basinward from the numerous canyons and gullies that incise the slopes of the Beringian margin and of Bowers Ridge and some places along the Aleutian Ridge. These Beringian and Bowers canyon sediment sources, however, appear to have contributed less modern sediment to the Aleutian basin than the large, well-defined channel systems that emanate from Bering, Umnak, and Amchitka submarine canyons and extend for several hundred kilometers across the abyssal plain. This GLORIA imagery emphasizes the important contribution of the Aleutian Ridge to modern sedimentation in the deep Bering Sea.

  12. The Ionian Abyssal Plain (central Mediterranean Sea): Morphology, subbottom structures and geodynamic history an inventory

    NASA Astrophysics Data System (ADS)

    Hieke, W.; Hirschleber, H. B.; Dehghani, G. A.

    2003-09-01

    In order to understand the structure and evolution of the Mediterranean Ridge accretionary complex, it is necessary to understand the structure and history of its foreland. The Ionian Abyssal Plain is one of the varying types of foreland. The state of knowledge for that is presented. Its contour and detailed relief are described for the first time. Based on published and hitherto unpublished seismic data, information on the thickness of the Plio-Quaternary and on the Messinian evaporites are presented. Of particular interest are data concerning the pre-Messinian reflectors. They indicate a pattern of tilted blocks and horst-like features created in pre-Messinian time by tensional tectonics. Varying subsidence continued, however, during Messinian time and controlled the thickness of evaporites. At some places (e.g. Victor Hensen Seahill) vertical tectonics seem to be still active. The main tectonic structures of the Ionian Abyssal Plain are not related to the process of the present accretion and subduction at the Africa/Eurasia plate boundary but are pre-existing and should influence the internal structure of the Mediterranean Ridge which is still growing at the expense of the foreland. As a consequence of our structural evidence, we favour the following interpretation: the Ionian Abyssal Plain is not a remainder of the Jurassic Tethyan ocean but originated by extensive attenuation of continental crust.

  13. The Mars Hill Terrane: An enigmatic southern Appalachian terrane

    SciTech Connect

    Raymond, L.A.; Johnson, P.A. . Dept. of Geology)

    1994-03-01

    The Mars Hill Terrane (MHT) in the Appalachian Blue Ride Belt is bordered by complex, locally reactivated thrust and strike-slip faults. On the east, the MHT is bounded by the allochthonous, ensimatic Toe Terrane (TT) across the diachronous, ductile Holland Mountain-Soque River Fault System. The MHT is separated on the northwest from ensialic Laurentian basement (LB), by the Fries-Hayesville Fault System. On the south, the MHT is truncated by the Shope Fork Fault. The MHT is characterized by migmatitic biotite-pyroxene-hornblende gneiss, but contains 1--1.8 b.y. old quartz-feldspar gneisses, plus ultramafic rocks, calc-silicate rocks, mica schists and gneisses, and Neoproterozoic Bakersville gabbros. This rock assemblage contrasts with that of the adjoining terranes. The only correlative units between the MHT and adjoining terranes are Neoproterozoic gabbro, Ordovician-Devonian granitoid plutons, and ultramafic rocks. Gabbro links the MHT with LB rocks. Apparently similar calc-silicate rocks differ petrographically among terranes. During Taconic or Acadian events, both the TT and MHT reached amphibolite to granulite metamorphic grade, but the LB did not exceed greenschist grade. The data conflict. The O-D plutons, ultramafic rocks, and metamorphic histories suggest that the TT had docked with the MHT by Ordovician time. The premetamorphic character of the Holland Mtn.-Soque River Fault System supports that chronology. Neoproterozoic gabbros suggest a MHT-LB link by Cambrian time, but the LB experienced neither O-D plutonism nor Paleozoic amphibolite-granulite facies metamorphism.

  14. Interseismic Strain Accumulation Across Metropolitan Los Angeles: Puente Hills Thrust

    NASA Astrophysics Data System (ADS)

    Argus, D.; Liu, Z.; Heflin, M. B.; Moore, A. W.; Owen, S. E.; Lundgren, P.; Drake, V. G.; Rodriguez, I. I.

    2012-12-01

    Twelve years of observation of the Southern California Integrated GPS Network (SCIGN) are tightly constraining the distribution of shortening across metropolitan Los Angeles, providing information on strain accumulation across blind thrust faults. Synthetic Aperture Radar Interferometry (InSAR) and water well records are allowing the effects of water and oil management to be distinguished. The Mojave segment of the San Andreas fault is at a 25° angle to Pacific-North America plate motion. GPS shows that NNE-SSW shortening due to this big restraining bend is fastest not immediately south of the San Andreas fault across the San Gabriel mountains, but rather 50 km south of the fault in northern metropolitan Los Angeles. The GPS results we quote next are for a NNE profile through downtown Los Angeles. Just 2 mm/yr of shortening is being taken up across the San Gabriel mountains, 40 km wide (0.05 micro strain/yr); 4 mm/yr of shortening is being taken up between the Sierra Madre fault, at the southern front of the San Gabriel mountains, and South Central Los Angeles, also 40 km wide (0.10 micro strain/yr). We find shortening to be more evenly distributed across metropolitan Los Angeles than we found before [Argus et al. 2005], though within the 95% confidence limits. An elastic models of interseismic strain accumulation is fit to the GPS observations using the Back Slip model of Savage [1983]. Rheology differences between crystalline basement and sedimentary basin rocks are incorporated using the EDGRN/EDCMP algorithm of Wang et al. [2003]. We attempt to place the Back Slip model into the context of the Elastic Subducting Plate Model of Kanda and Simons [2010]. We find, along the NNE profile through downtown, that: (1) The deep Sierra Madre Thrust cannot be slipping faster than 2 mm/yr, and (2) The Puente Hills Thrust and nearby thrust faults (such as the upper Elysian Park Thrust) are slipping at 9 ±2 mm/yr beneath a locking depth of 12 ±5 km (95% confidence limits

  15. Age and paragenesis of mineralisation at Coronation Hill uranium deposit, Northern Territory, Australia

    NASA Astrophysics Data System (ADS)

    Orth, Karin; Meffre, Sebastien; Davidson, Garry

    2014-06-01

    Coronation Hill is a U + Au + platinum group elements deposit in the South Alligator Valley (SAV) field in northern Australia, south of the better known unconformity-style U East Alligator Rivers (EAR) field. The SAV field differs from the EAR by having a more complex basin-basement architecture. A volcanically active fault trough (Jawoyn Sub-basin) developed on older basement and then was disrupted by renewed faulting, before being buried beneath regional McArthur Basin sandstones that are also the main hanging wall to the EAR deposits. Primary mineralisation at Coronation Hill formed at 1607 ± 26 Ma (rather than 600-900 Ma as previously thought), and so it is likely that the SAV was part of a single west McArthur Basin dilational event. Most ore is hosted in sub-vertical faults and breccias in the competent volcanic cover sequence. This favoured fluid mixing, acid buffering (forming illite) and oxidation of Fe2+ and reduced C-rich assemblages as important uranium depositional mechanisms. However, reduction of U in fractured older pyrite (Pb model age of 1833 ± 67 Ma) is an important trap in diorite. Some primary ore was remobilised at 675 ± 21 Ma to form coarse uraninite + Ni-Co pyrite networks containing radiogenic Pb. Coronation Hill is polymetallic, and in this respect resembles the `egress'-style U deposits in the Athabascan Basin (Canada). However, these are all cover-hosted. A hypothesis for further testing is that Coronation Hill is also egress-style, with ores formed by fluids rising through basement-hosted fault networks (U reduction by diorite pyrite and carbonaceous shale), and into veins and breccias in the overlying Jawoyn Sub-basin volcano-sedimentary succession.

  16. Controls on melting at spreading ridges from correlated abyssal peridotite - mid-ocean ridge basalt compositions

    NASA Astrophysics Data System (ADS)

    Regelous, Marcel; Weinzierl, Christoph G.; Haase, Karsten M.

    2016-09-01

    Variations in the volume and major element composition of basalt erupted along the global mid-ocean ridge system have been attributed to differences in mantle potential temperature, mantle composition, or plate spreading rate and lithosphere thickness. Abyssal peridotites, the residues of mantle melting beneath mid-ocean ridges, provide additional information on the melting process, which could be used to test these hypotheses. We compiled a global database of abyssal peridotite compositions averaged over the same ridge segments defined by Gale et al. (2013). In addition, we calculated the distance of each ridge segment to the nearest hotspots. We show that Cr# in spinel in abyssal peridotites is negatively correlated with Na90 in basalts from the same ridge segments on a global scale. Ridge segments that erupt basalts apparently produced by larger degrees of mantle melting are thus underlain by peridotites from which large amounts of melt have been extracted. We find that near-ridge hotspots have a more widespread influence on mid-ocean ridge basalt (MORB) composition and ridge depth than previously thought. However, when these hotspot-influenced ridge segments are excluded, the remaining segments show clear relationships between MORB composition, peridotite composition, and ridge depth with spreading rate. Very slow-spreading ridges (<20 mm/yr) are deeper, erupt basalts with higher Na90, Al90, K90/Ti90, and lower Fe90, Ca90/Al90, and expose peridotites with lower Cr# than intermediate and fast-spreading ridges. We show that away from hotspots, the spreading-rate dependence of the maximum degree of mantle melting inferred from Cr# in peridotites (FM) and the bulk degree of melting inferred from Na90 in basalts (FB) from the same ridge segments is unlikely to be due to variations in mantle composition. Nor can the effects of dynamic mantle upwelling or incomplete melt extraction at low spreading rates satisfactorily explain the observed compositions of abyssal

  17. Northern San Andreas fault near Shelter Cove, California

    USGS Publications Warehouse

    Prentice, C.S.; Merritts, D.J.; Beutner, E.C.; Bodin, P.; Schill, A.; Muller, J.R.

    1999-01-01

    The location of the San Andreas fault in the Shelter Cove area of northern California has been the subject of long-standing debate within the geological community. Although surface ruptures were reported near Shelter Cove in 1906, several subsequent workers questioned whether these ruptures represented true fault slip or shaking-related, gravity-driven deformation. This study, involving geologic and geomorphic mapping, historical research, and excavation across the 1906 rupture zone, concludes that the surface ruptures reported in 1906 were the result of strike-slip faulting, and that a significant Quaternary fault is located onshore near Shelter Cove. Geomorphic arguments suggest that the Holocene slip rate of this fault is greater than about 14 mm/yr, indicating that it plays an important role within the modern plate-boundary system. The onshore trace of the fault zone is well expressed as far north as Telegraph Hill; north of Telegraph Hill, its location is less well-constrained, but we propose that a splay of the fault may continue onshore northward for at least 9 km to the vicinity of Saddle Mountain.

  18. Puente Hills blind-thrust system, Los Angeles, California

    USGS Publications Warehouse

    Shaw, J.H.; Plesch, A.; Dolan, J.F.; Pratt, T.L.; Fiore, P.

    2002-01-01

    We describe the three-dimensional geometry and Quaternary slip history of the Puente Hills blind-thrust system (PHT) using seismic reflection profiles, petroleum well data, and precisely located seismicity. The PHT generated the 1987 Whittier Narrows (moment magnitude [Mw] 6.0) earthquake and extends for more than 40 km along strike beneath the northern Los Angeles basin. The PHT comprises three, north-dipping ramp segments that are overlain by contractional fault-related folds. Based on an analysis of these folds, we produce Quaternary slip profiles along each ramp segment. The fault geometry and slip patterns indicate that segments of the PHT are related by soft-linkage boundaries, where the fault ramps are en echelon and displacements are gradually transferred from one segment to the next. Average Quaternary slip rates on the ramp segments range from 0.44 to 1.7 mm/yr, with preferred rates between 0.62 and 1.28 mm/yr. Using empirical relations among rupture area, magnitude, and coseismic displacement, we estimate the magnitude and frequency of single (Mw 6.5-6.6) and multisegment (Mw 7.1) rupture scenarios for the PHT.

  19. Slip and Dilation Tendency Anlysis of McGinness Hills Geothermal Area

    DOE Data Explorer

    Faulds, James E.

    2013-12-31

    Slip and Dilation Tendency in focus areas Critically stressed fault segments have a relatively high likelihood of acting as fluid flow conduits (Sibson, 1994). As such, the tendency of a fault segment to slip (slip tendency; Ts; Morris et al., 1996) or to dilate (dilation tendency; Td; Ferrill et al., 1999) provides an indication of which faults or fault segments within a geothermal system are critically stressed and therefore likely to transmit geothermal fluids. The slip tendency of a surface is defined by the ratio of shear stress to normal stress on that surface: Ts = τ / σn (Morris et al., 1996). Dilation tendency is defined by the stress acting normal to a given surface: Td = (σ1-σn) / (σ1-σ3) (Ferrill et al., 1999). Slip and dilation were calculated using 3DStress (Southwest Research Institute). Slip and dilation tendency are both unitless ratios of the resolved stresses applied to the fault plane by ambient stress conditions. Values range from a maximum of 1, a fault plane ideally oriented to slip or dilate under ambient stress conditions to zero, a fault plane with no potential to slip or dilate. Slip and dilation tendency values were calculated for each fault in the focus study areas at, McGinness Hills, Neal Hot Springs, Patua, Salt Wells, San Emidio, and Tuscarora on fault traces. As dip is not well constrained or unknown for many faults mapped in within these we made these calculations using the dip for each fault that would yield the maximum slip tendency or dilation tendency. As such, these results should be viewed as maximum tendency of each fault to slip or dilate. The resulting along-fault and fault-to-fault variation in slip or dilation potential is a proxy for along fault and fault-to-fault variation in fluid flow conduit potential. Stress Magnitudes and directions Stress field variation within each focus area was approximated based on regional published data and the world stress database (Hickman et al., 2000; Hickman et al., 1998

  20. Glacial magnetite dissolution in abyssal NW Pacific sediments - evidence for carbon trapping?

    NASA Astrophysics Data System (ADS)

    Korff, Lucia; von Dobeneck, Tilo; Frederichs, Thomas; Kasten, Sabine; Kuhn, Gerhard; Gersonde, Rainer; Diekmann, Bernhard

    2016-04-01

    The abyssal North Pacific Ocean's large volume, depth, and terminal position on the deep oceanic conveyor make it a candidate site for deep carbon trapping as postulated by climate theory to explain the massive glacial drawdown of atmospheric CO2. As the major basins of the North Pacific have depths of 5500-6500m, far below the modern and glacial Calcite Compensation Depths (CCD), these abyssal sediments are carbonate-free and therefore not suitable for carbonate-based paleoceanographic proxy reconstructions. Instead, paleo-, rock and environmental magnetic methods are generally well applicable to hololytic abyssal muds and clays. In 2009, the international paleoceanographic research cruise SO 202 INOPEX ('Innovative North Pacific Experiment') of the German RV SONNE collected two ocean-spanning EW sediment core transects of the North Pacific and Bering Sea recovering a total of 50 piston and gravity cores from 45 sites. Out of seven here considered abyssal Northwest Pacific piston cores collected at water depths of 5100 to 5700m with mostly coherent shipboard susceptibility logs, the 20.23m long SO202-39-3, retrieved from 5102 m water depth east of northern Shatsky Rise (38°00.70'N, 164°26.78'E), was rated as the stratigraphically most promising record of the entire core transect and selected for detailed paleo- and environmental magnetic, geochemical and sedimentological investigations. This core was dated by correlating its RPI and Ba/Ti records to well-dated reference records and obviously provides a continuous sequence of the past 940 kyrs. The most striking orck magnetic features are coherent magnetite-depleted zones corresponding to glacial periods. In the interglacial sections, detrital, volcanic and even submicron bacterial magnetite fractions are excellently preserved. These alternating magnetite preservation states seem to reflect dramatic oxygenation changes in the deep North Pacific Ocean and hint at large-scale benthic glacial carbon trapping

  1. Geologic map of Paleozoic rocks in the Calico Hills, Nevada Test Site, southern Nevada

    SciTech Connect

    Cole, J.C.; Cashman, P.H.

    1998-11-01

    The Calico Hills area in the southwestern part of the Nevada Test Site, Nye County, Nevada, exposes a core of pre-Tertiary rocks surrounded by middle Miocene volcanic strata. This map portrays the very complex relationships among the pre-Tertiary stratigraphic units of the region. The Devonian and Mississippian rocks of the Calico Hills are distinct from age-equivalent carbonate-shelf or submarine-fan strata in other parts of the Nevada Test Site. The Calico Hills strata are interpreted to have been deposited beyond the continental shelf edge from alternating silicic and carbonate clastic sources. Structures of the Calico Hills area record the compounded effects of: (1) eastward-directed, foreland-vergent thrusting; (2) younger folds, kink zones, and thrusts formed by hinterland-vergent deformation toward northwesterly and northerly directions; and (3) low-angle normal faults that displaced blocks of Middle Paleozoic carbonate strata across the contractionally deformed terrane. All of these structures are older than any of the middle Miocene volcanic rocks that were erupted across the Calico Hills.

  2. Oblique strike-slip faulting of the Cascadia submarine forearc: The Daisy Bank fault zone off central Oregon

    NASA Astrophysics Data System (ADS)

    Goldfinger, Chris; Kulm, LaVerne D.; Yeats, Robert S.; Hummon, Cheryl; Huftile, Gary J.; Niem, Alan R.; McNeill, Lisa C.

    The Cascadia submarine forearc off Oregon and Washington is deformed by numerous active WNW-trending, left-lateral strike-slip faults. The kinematics of this set of sub-parallel left-lateral faults suggests clockwise block rotation of the forearc driven by oblique subduction. One major left-lateral strike-slip fault, the 94 km-long Daisy Bank fault, located off central Oregon, was studied in detail using high-resolution AMS 150 kHz and SeaMARC-lA sidescan sonar, swath bathymetry, multichannel seismic reflection profiles and a submersible. The Daisy Bank fault zone cuts the sediments and basaltic basement of the subducting Juan de Fuca plate, and the overriding North American plate, extending from the abyssal plain to the upper slope-outer shelf region. The Daisy Bank fault, a near-vertical left-lateral fault striking 292°, is a wide structural zone with multiple scarps observed in high-resolution sidescan images. From a submersible, we observe that these scarps offset late Pleistocene gray clay and overlying olive green Holocene mud, dating fault activity as post-12 ka on the upper slope. Vertical separation along individual fault scarps ranges from a few centimeters to 130 meters. Using a retrodeformation technique with multichannel reflection records, we calculate a net slip of 2.2±0.5 km. Fault movement commenced at about 380±50 ka near the western fault tip, based upon an analysis of growth strata and correlation with deep-sea drill hole biostratigraphy. We calculate a slip rate of 5.7±2.0 mm/yr. for the Daisy Bank fault at its western end on the Juan de Fuca plate. The motion of the set of oblique faults, including the Daisy Bank fault, may accommodate a significant portion of the oblique component of plate motion along the central Cascadia margin. We propose a block rotation model by which the seawardmost part of the forearc rotates clockwise and translates northward.

  3. Cu refertilization of abyssal harzburgites by melt percolation

    NASA Astrophysics Data System (ADS)

    Ciazela, Jakub; Dick, Henry; Koepke, Juergen; Botcharnikov, Roman; Muszynski, Andrzej; Kuhn, Thomas

    2015-04-01

    Primitive mantle is depleted in many elements by partial melting processes, but it can be subsequently refertilized by impregnation with percolating melts. It is known that Cu can be enriched in primitive melts, depleting mantle residue, due to the former process (Patten et al. 2013). However, the behavior of Cu in the processes of mantle-melt interaction is poorly understood. The only comprehensive study is based on compositions of orogenic peridotites, representing the subcontinental mantle (Lorand et al. 1993; 2013), where a moderate enrichment of the mantle in Cu (up to ~50 ppm) has been observed. Here, we present the first results obtained for a suite of rocks from an oceanic core complex (OCC), the Kane Megamullion at 22°30'N at the Mid-Atlantic Ridge (Dick et al. 2008). OCC's provide large exposures of mantle and lower crustal rocks on the seafloor on detachment fault footwalls at slow and ultraslow spreading ridges. The mantle rocks are composed of spinel and plagioclase harzburgites. The spinel harzburgites represent depleted mantle, whereas the plagioclase harzburgites were formed by subsequent late-stage melt impregnation in the depleted mantle (Dick et al. 2010). We have determined Cu concentrations in 22 residual spinel harzburgites and 4 plagioclase harzburgites using total digestion ICP-MS. The average Cu concentration in spinel harzburgites is 35±11 ppm Cu (2σ). The average Cu concentration obtained for plagioclase harzburgites is 131±33 ppm Cu (2σ). Additionally, we have analyzed one 1.5 cm thick contact zone between an oxide gabbro vein and residual peridotite. The contact zone, which has been heavily impregnated by the melt, contains 284 ppm Cu. In contrast, the neighboring oxide gabbro vein and the hosting peridotite contain 147 and 68 ppm Cu, respectively. Furthermore, we have determined the concentration of Cu in a dunite (118 ppm), formed in a reaction between the mantle and melt ascending through the lithosphere (Dick et al. 2010

  4. 6. Detail of pilaster cap. Aug. 10, 1936. Joseph Hill, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Detail of pilaster cap. Aug. 10, 1936. Joseph Hill, photographer, copied from small photo taken by survey member. - Jansonist Colony, Steeple Building, Main & Bishop Hill Streets, Bishop Hill, Henry County, IL

  5. 3. West and south elevations. Joseph Hill, photographer, copied from ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. West and south elevations. Joseph Hill, photographer, copied from photo lent by Evelyn S. Craig. August 1936. - Jansonist Colony, Steeple Building, Main & Bishop Hill Streets, Bishop Hill, Henry County, IL

  6. 1. Historic American Buildings Survey Joseph Hill, Photographer August 1936 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Historic American Buildings Survey Joseph Hill, Photographer August 1936 FIRST ORIGINAL STORE AND POSTOFFICE, COPY OF AN EARLY PHOTOGRAPH. LENT BY EVELYN S. CRAIG - Jansonist Colony, Colony Store & Post Office, Main & Bishop Hill Streets, Bishop Hill, Henry County, IL

  7. 7. Detail of balcony rail. August 1936. Joseph Hill, photographer, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. Detail of balcony rail. August 1936. Joseph Hill, photographer, copied from small photo taken by survey member. - Jansonist Colony, Steeple Building, Main & Bishop Hill Streets, Bishop Hill, Henry County, IL

  8. Unexpectedly higher metazoan meiofauna abundances in the Kuril-Kamchatka Trench compared to the adjacent abyssal plains

    NASA Astrophysics Data System (ADS)

    Schmidt, Christina; Martínez Arbizu, Pedro

    2015-01-01

    We studied meiofauna standing stocks and community structure in the Kuril-Kamchatka Trench and its adjacent abyssal plains in the northwestern Pacific Ocean. In general, the Nematoda were dominant (93%) followed by the Copepoda (4%). Nematode abundances ranged from 87% to 96%; those of copepods from 2% to 7%. The most diverse deployment yielded 17 taxa: Acari, Amphipoda, Annelida, Bivalvia, Coelenterata, Copepoda, Cumacea, Gastrotricha, Isopoda, Kinorhyncha, Loricifera, Nematoda, Ostracoda, Priapulida, Tanaidacea, Tantulocarida, and Tardigrada. Nauplii were also present. Generally, the trench slope and the southernmost deployments had the highest abundances (850-1392 individuals/cm2). The results of non-metric multidimensional scaling indicated that these deployments were similar to each other in meiofauna community structure. The southernmost deployments were located in a zone of higher particulate organic carbon (POC) flux (g Corg m-2 yr-1), whereas the trench slope should have low POC flux due to depth attenuation. Also, POC and abundance were significantly correlated in the abyssal plains. This correlation may explain the higher abundances at the southernmost deployments. Lateral transport was also assumed to explain high meiofauna abundances on the trench slope. Abundances were generally higher than expected from model results. ANOSIM revealed significant differences between the trench slope and the northern abyssal plains, between the central abyssal plains and the trench slope, between the trench slope and the southern abyssal plains, between the central and the southern abyssal plains, and between the central and northern deployments. The northern and southern abyssal plains did not differ significantly. In addition, a U-test revealed highly significant differences between the trench-slope and abyssal deployments. The taxa inhabited mostly the upper 0-3 cm of the sediment layer (Nematoda 80-90%; Copepoda 88-100%). The trench-slope and abyssal did not differ

  9. Report on the Black Hills Alliance.

    ERIC Educational Resources Information Center

    Ryan, Joe

    1979-01-01

    A rally to save the Black Hills from coal- and uranium-greedy energy companies was held on July 6 and over 2,000 joined in a 15-mile walk on July 7 in Rapid City, South Dakota. The Black Hills Alliance, an Indian coalition concerned about energy development proposals in the Great Plains, sponsored the gathering. (NQ)

  10. Colleges as Shining Cities on a Hill

    ERIC Educational Resources Information Center

    Townsend, Kathleen Kennedy

    2012-01-01

    In this article, the author proposes that the notion of America be reintroduced as the "shining city on a hill," that abiding image from American history. The image of the shining city on a hill captures the imagination because it reflects the abiding truth that people become fully human in society, not outside of it. People need one another to…

  11. Glaciated appalachian plateau: till shadows on hills.

    PubMed

    Coates, D R

    1966-06-17

    North slopes are twice as steep as south slopes on the hills of central New York. This asymmetry is caused by unequal till thickness-3.6 meters on north slopes and 27.6 meters on south slopes. Previous workers interpreted the hills as being of bedrock sculptured by glacial erosion, with till 0.9 to 3 meters thick. PMID:17755398

  12. Counseling Uses of the Hill Interaction Matrix.

    ERIC Educational Resources Information Center

    Boyd, Robert E.

    While the Hill Interaction Matrix was developed as a research instrument to assess interview process, it is also generally useful in any undertaking requiring the evaluation of verbal interaction and, hence, can be used as an aid in modifying communication in order to increase its therapeutic effect. The Hill Interaction Matrix with accompanying…

  13. Long-term maintenance and public exhibition of deep-sea hydrothermal fauna: The AbyssBox project

    NASA Astrophysics Data System (ADS)

    Shillito, Bruce; Ravaux, Juliette; Sarrazin, Jozée; Zbinden, Magali; Sarradin, Pierre-Marie; Barthelemy, Dominique

    2015-11-01

    The AbyssBox project aims to provide the first permanent public exhibition of live deep-sea hydrothermal fauna maintained at in situ pressure. AbyssBox is a pressurized aquarium designed to function permanently. Here we present details of the project after the public exhibition functioned for more than three years at Océanopolis aquarium in Brest, France. We also describe the AbyssBox pressure aquarium, and provide data and observations on vent shrimp (Mirocaris fortunata) and crabs (Segonzacia mesatlantica) that were sampled from 1700 m depth at the Lucky Strike vent field (Mid-Atlantic Ridge) during different cruises. While mortalities exceeded 50% during the first days following sampling, the remaining animals appeared to acclimate fairly well. Some crabs have now been kept for more than 2 years, and some shrimp have spent more than 3 years in captivity. Primarily designed for a public exhibition, the AbyssBox is already used for scientific purposes, since it provides one of the most effective tools for long-term rearing of deep-sea fauna. AbyssBox is a first step towards maintaining a variety of deep-sea fauna year-round at in situ pressure, which will serve both scientific and public interests.

  14. Evaluation of the Location and Recency of Faulting Near Prospective Surface Facilities in Midway Valley, Nye County, Nevada

    USGS Publications Warehouse

    Swan, F.H.; Wesling, J.R.; Angell, M.M.; Thomas, A.P.; Whitney, J.W.; Gibson, J.D.

    2001-01-01

    Evaluation of surface faulting that may pose a hazard to prospective surface facilities is an important element of the tectonic studies for the potential Yucca Mountain high-level radioactive waste repository in southwestern Nevada. For this purpose, a program of detailed geologic mapping and trenching was done to obtain surface and near-surface geologic data that are essential for determining the location and recency of faults at a prospective surface-facilities site located east of Exile Hill in Midway Valley, near the eastern base of Yucca Mountain. The dominant tectonic features in the Midway Valley area are the north- to northeast-trending, west-dipping normal faults that bound the Midway Valley structural block-the Bow Ridge fault on the west side of Exile Hill and the Paint-brush Canyon fault on the east side of the valley. Trenching of Quaternary sediments has exposed evidence of displacements, which demonstrate that these block-bounding faults repeatedly ruptured the surface during the middle to late Quaternary. Geologic mapping, subsurface borehole and geophysical data, and the results of trenching activities indicate the presence of north- to northeast-trending faults and northwest-trending faults in Tertiary volcanic rocks beneath alluvial and colluvial sediments near the prospective surface-facilities site. North to northeast-trending faults include the Exile Hill fault along the eastern base of Exile Hill and faults to the east beneath the surficial deposits of Midway Valley. These faults have no geomorphic expression, but two north- to northeast-trending zones of fractures exposed in excavated profiles of middle to late Pleistocene deposits at the prospective surface-facilities site appear to be associated with these faults. Northwest-trending faults include the West Portal and East Portal faults, but no disruption of Quaternary deposits by these faults is evident. The western zone of fractures is associated with the Exile Hill fault. The eastern

  15. Evaluation of the location and recency of faulting near prospective surface facilities in Midway Valley, Nye County, Nevada

    SciTech Connect

    Swan, F.H.; Wesling, J.R.; Angell, M.M.; Thomas, A.P.; Whitney, J.W.; Gibson, J.D.

    2002-01-17

    Evaluation of surface faulting that may pose a hazard to prospective surface facilities is an important element of the tectonic studies for the potential Yucca Mountain high-level radioactive waste repository in southwestern Nevada. For this purpose, a program of detailed geologic mapping and trenching was done to obtain surface and near-surface geologic data that are essential for determining the location and recency of faults at a prospective surface-facilities site located east of Exile Hill in Midway Valley, near the eastern base of Yucca Mountain. The dominant tectonic features in the Midway Valley area are the north- to northeast-trending, west-dipping normal faults that bound the Midway Valley structural block-the Bow Ridge fault on the west side of Exile Hill and the Paint-brush Canyon fault on the east side of the valley. Trenching of Quaternary sediments has exposed evidence of displacements, which demonstrate that these block-bounding faults repeatedly ruptured the surface during the middle to late Quaternary. Geologic mapping, subsurface borehole and geophysical data, and the results of trenching activities indicate the presence of north- to northeast-trending faults and northwest-trending faults in Tertiary volcanic rocks beneath alluvial and colluvial sediments near the prospective surface-facilities site. North to northeast-trending faults include the Exile Hill fault along the eastern base of Exile Hill and faults to the east beneath the surficial deposits of Midway Valley. These faults have no geomorphic expression, but two north- to northeast-trending zones of fractures exposed in excavated profiles of middle to late Pleistocene deposits at the prospective surface-facilities site appear to be associated with these faults. Northwest-trending faults include the West Portal and East Portal faults, but no disruption of Quaternary deposits by these faults is evident. The western zone of fractures is associated with the Exile Hill fault. The eastern

  16. Solar Rossby Wave 'Hills' Identified As Supergranules

    NASA Technical Reports Server (NTRS)

    Williams, P. E.; Hathaway, David H.; Cuntz, M.

    2007-01-01

    We explore the nature of 'hills' observed on the solar surface which had previously been attributed to Rossby waves. We investigate the sol ar hills phenomenon by analyzing the output from a synthetic model ba sed solely on the observed solar photospheric convection spectrum. We show that the characteristics of these hills can be explained by the corrugation of the surface produced by the radial flows of the conve ction. The hills in our simulations are dominated by supergranules, a well-known component of solar convection. Rossby waves have been predicted to exist within the Sun and may play an important role in the d ynamics of the solar interior, including the Sun's differential rotat ion and magnetic dynamo. Our study suggests, however, that the hills observed at the solar limb do not confirm the existence of solar Ross by waves.

  17. Fault failure with moderate earthquakes

    USGS Publications Warehouse

    Johnston, M.J.S.; Linde, A.T.; Gladwin, M.T.; Borcherdt, R.D.

    1987-01-01

    High resolution strain and tilt recordings were made in the near-field of, and prior to, the May 1983 Coalinga earthquake (ML = 6.7, ?? = 51 km), the August 4, 1985, Kettleman Hills earthquake (ML = 5.5, ?? = 34 km), the April 1984 Morgan Hill earthquake (ML = 6.1, ?? = 55 km), the November 1984 Round Valley earthquake (ML = 5.8, ?? = 54 km), the January 14, 1978, Izu, Japan earthquake (ML = 7.0, ?? = 28 km), and several other smaller magnitude earthquakes. These recordings were made with near-surface instruments (resolution 10-8), with borehole dilatometers (resolution 10-10) and a 3-component borehole strainmeter (resolution 10-9). While observed coseismic offsets are generally in good agreement with expectations from elastic dislocation theory, and while post-seismic deformation continued, in some cases, with a moment comparable to that of the main shock, preseismic strain or tilt perturbations from hours to seconds (or less) before the main shock are not apparent above the present resolution. Precursory slip for these events, if any occurred, must have had a moment less than a few percent of that of the main event. To the extent that these records reflect general fault behavior, the strong constraint on the size and amount of slip triggering major rupture makes prediction of the onset times and final magnitudes of the rupture zones a difficult task unless the instruments are fortuitously installed near the rupture initiation point. These data are best explained by an inhomogeneous failure model for which various areas of the fault plane have either different stress-slip constitutive laws or spatially varying constitutive parameters. Other work on seismic waveform analysis and synthetic waveforms indicates that the rupturing process is inhomogeneous and controlled by points of higher strength. These models indicate that rupture initiation occurs at smaller regions of higher strength which, when broken, allow runaway catastrophic failure. ?? 1987.

  18. Layered Rocks in 'Columbia Hills'

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This black-and-white image shows the first layered rocks scientists have seen close up in Gusev Crater, where NASA's Mars Exploration Rover Spirit landed Jan. 4, 2004. While Spirit's twin rover, Opportunity, reached the stadium-size Endurance Crater on the other side of Mars and began exploring its many layered outcrops in early May, Spirit traveled more than 3.5 kilometers (2.2 miles) to get to this layered bedrock in the 'Columbia Hills.' Scientists are planning to conduct a study of these rocks to determine if they are volcanic or sedimentary in origin, and if they have been chemically altered. Spirit's panoramic camera took this image on sol 217 (Aug. 13, 2004).

  19. Moored observations of episodic abyssal flow and mixing at station ALOHA

    NASA Astrophysics Data System (ADS)

    Alford, M. H.; Lukas, Roger; Howe, Bruce; Pickering, Andy; Santiago-Mandujano, Fernando

    2011-08-01

    Moored measurements of abyssal velocity and temperature are presented with a focus on episodic cold overflow events first observed by Lukas et al. (2001) in the Hawaii Ocean Time-series (HOT), a 23-year-long time series of ≈ monthly CTD profiles at station ALOHA (22.75°N, 158°W). Three major cold events were observed in our 2.5-year record, of which we present one in detail. The event appeared in two pulses spaced by about two weeks, wherein potential temperature anomaly was <-0.015°C over the bottom 600 m. Flow was about 10 cms-1 to the southwest, confirming earlier interpretations of the events as overflows from the Maui deep to the east. Between the two pulses, flow veered to the northwest, possibly associated with seiching. Speed decreased rapidly below the sill depth (≈4625) m, suggesting sheltering by the basin walls. The associated shear, even smoothed over 200 m and not including internal waves, was nearly unstable to Kelvin-Helmholtz instability. During this period, a large mixed region was observed wherein the lower 240 m was homogenized, remaining so for 14 hours (1.2 buoyancy periods). From Thorpe scale analysis, the implied diffusivity of the event was (0.5-4.5) × 10-1m2s-1. No other overturning events greater than 50 m high were observed in the record, suggesting that abyssal mixing is strongly intermittent. We suggest that such intermittency in abyssal mixing and flow is likely the rule rather than the exception, calling for more highly temporally resolved observations.

  20. A comparison of benthic infaunal abundance on two abyssal plains in the northeast Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Carey, Andrew G.

    1981-05-01

    Benthic macro-infauna were sampled in the northeast Pacific Ocean at 12 stations on an east-west transect across Cascadia and Eastern Tufts abyssal plains to determine ecological effects of continental influences and depth on those communities. The two plains, separated by the East Pacific Rise, differ in depth and distance from the continental margin. Tufts Plain lies to the west; primary production in the overlying water and the amount of organic carbon in the surface sediments are lower than for the Cascadia Plain region. Five benthic ecological zones were distinguished: (1) Cascadia Plain Slope-Base; (2) Eastern Cascadia Plain; (3) Cascadia Deep-Sea Channel; (4) Western Cascadia Plain; and (5) Eastern Tufts Plain. These differ in faunal biomass, numerical density, gross composition of the fauna by phyla, and composition of sediment. Comparatively, the slope-base environment supports the most abundant fauna. The numerical density of infauna on Eastern Tufts Plain is similar to that on Eastern and Western Cascadia Plain; however, the biomass tends to be lower in the deeper, more distant environment. It is concluded that these differences in the benthic fauna are probably caused by varying levels of input from primary production in overlying waters and differences in the transport of organic-rich particles off the continental shelf. Distance-related environmental characteristics are shown to be critical in the deep sea for controlling benthic community structure. On Cascadia Abyssal Plain, a plateau-like feature, the gross structure of communities changes with increasing distance from the continent but at constant depth. Faunal densities, biomass, and composition by phyla lie within the range of values normally associated with upper abyssal environments.

  1. Possible reactivation of the Vincent-Chocolate Mountains thrust in the Gavilan Hills area, southeasternmost California

    SciTech Connect

    Oyarzabal, F.R.; Jacobson, C.E. ); Haxel, G.B. )

    1993-04-01

    The Late Cretaceous-early Tertiary Orocopia Schist (OS) of southeasternmost California consists of metamorphosed continental margin sedimentary and basaltic rocks, overlain by an upper plate of continental crust along the Vincent-Chocolate Mountains fault (VCMF). Previous analysis of late folds and shear band in OS and upper plate in the Gavilan Hills and adjacent ares indicated that the direction of transport of the upper plate was northeastward. This has been considered evidence of a SW dipping subduction zone, along which an outboard continental fragment was sutured to North America. Another view is that the VCMF was formed by underplating of the OS in an Andean continental margin, and that the NE-vergent late structures formed during uplift of the OS. The authors' continuing work in the Gavilan Hills confirm the NE sense of vergence but suggests a more complex structural history. The schist is characterized by refolded folds, shear bands, and two penetrative lineations. An older lineation that ranges from N10[degree]E to N30[degree]E is widespread in the area, but is more evident at low structural levels. A second lineation ranges from N40[degree]E to N70[degree]E and is strongly developed in rocks near the VCMF. The complex folding pattern, presence of mylonitic schist, relative thinness of upper-plate mylonite, and possible retrogressive character of the shear bands suggest that the VCMF in the Gavilan Hills area may have been reactivated after original thrusting. The VCMF in the Gavilan Hills is intermediate in character between the probable subduction thrust in the San Gabriel Mountains and the reactivated faults in the Orocopia Mountains and areas surrounding the Gavilan Hills.

  2. An abyssal mobilome: viruses, plasmids and vesicles from deep-sea hydrothermal vents.

    PubMed

    Lossouarn, Julien; Dupont, Samuel; Gorlas, Aurore; Mercier, Coraline; Bienvenu, Nadege; Marguet, Evelyne; Forterre, Patrick; Geslin, Claire

    2015-12-01

    Mobile genetic elements (MGEs) such as viruses, plasmids, vesicles, gene transfer agents (GTAs), transposons and transpovirions, which collectively represent the mobilome, interact with cellular organisms from all three domains of life, including those thriving in the most extreme environments. While efforts have been made to better understand deep-sea vent microbial ecology, our knowledge of the mobilome associated with prokaryotes inhabiting deep-sea hydrothermal vents remains limited. Here we focus on the abyssal mobilome by reviewing accumulating data on viruses, plasmids and vesicles associated with thermophilic and hyperthermophilic Bacteria and Archaea present in deep-sea hydrothermal vents. PMID:25911507

  3. Seawater-derived rare earth element addition to abyssal peridotites during serpentinization

    NASA Astrophysics Data System (ADS)

    Frisby, Carl; Bizimis, Michael; Mallick, Soumen

    2016-04-01

    Serpentinized abyssal peridotites are evidence for active communication between the Earth's hydrosphere and the upper mantle, where exchange and retention of both major and trace elements occur. Bulk rock Nd isotopes in serpentinized abyssal peridotites imply interaction of seawater with the peridotite. In contrast, the Nd isotopes of clinopyroxenes from serpentinized abyssal peridotites retain their primary magmatic signature. It is currently unclear if, how and where seawater-derived Nd and other REE are being added or exchanged with the mantle peridotite minerals during serpentinization. To remedy this knowledge gap, we present in situ trace and major element concentrations, bulk rock and sequential leaching experiment trace element concentrations as well as Nd, Sr isotope data on refertilized and depleted serpentinized abyssal peridotites from the Southwest Indian Ridge. The secondary serpentine matrix and magnetite veins in these peridotites have elevated LREE concentrations, with variable negative Ce anomalies and large Rb, Sr, Pb and U enrichments that resemble seawater trace element patterns. The LREE concentrations in the serpentine phase are higher than those expected for the primary mantle mineralogy (olivine, orthopyroxene) based on data from relic clinopyroxenes and equilibrium partition coefficients. These data are consistent with seawater-derived REE addition to the peridotite during serpentinization. The bulk rocks have more radiogenic Sr and more unradiogenic Nd isotopes than their clinopyroxene (up to 8 εNd units lower than clinopyroxene). Sequential leaching experiments designed to mobilize secondary carbonates and Fe-oxides show even more unradiogenic Nd isotope ratios in the leachates than the bulk rock and clinopyroxene, approaching seawater compositions (up to 15 εNd units lower than clinopyroxene). Mass balance calculations using trace elements or Nd isotopes suggest that up to 30% of the bulk peridotite Nd budget is of seawater origin and

  4. High Resolution Seismic Imaging of the Trench Canyon Fault Zone, Mono Lake, Northeastern California

    NASA Astrophysics Data System (ADS)

    Novick, M. W.; Jayko, A. S.; Roeske, S.; McClain, J. S.; Hart, P. E.; Boyle, M.

    2009-12-01

    High resolution seismic imaging of Mono Lake, located in northeastern California, has revealed an approximately northwest striking fault in the area to the west of aerially exposed Negit Volcano. This fault, henceforth referred to as the Trench Canyon Fault (TCF), has also been mapped onshore along a correlating strike as far north as Cedar Hill Volcano, located to the northeast of the lake on the California/Nevada border. Onshore, the TCF was mapped for approximately 10 kilometers using air photos, DEM images, and standard geologic pace and compass mapping techniques. The TCF post- dates the last glacial maximum, evidenced by the cutting of wave cut benches along Cedar Hill Volcano. Relict, non-historic shorelines, left by the steady evaporation of Mono Lake beginning approximately 13k, are also repeatedly cut by the fault. Additional evidence of fault presence includes sag ponds, pressure ridges, tectonically fractured rocks, and normal fault scarps found along strike. Offshore, DEM images show a northeast striking structure to the northwest of Negit Volcano, which is co-linear with the onshore TCF. High resolution seismic imaging of the structure, using an applied acoustic/SIG mini-sparker system, reveals steeply dipping Holocene sediments, as well as volcanic deposits from active vents which have erupted in the last 1000 years, offset by the fault. Detailed structural analysis of the previously unstudied Trench Canyon Fault (TFC) and faults in the Cedar Hill region of northern California, along with seismic studies of sediments beneath Mono Lake not only allow for a better comprehension of this minor fault system, but provide greater understanding of the larger and more complex Walker Lane Shear Zone. Fault analyses, combined and correlated with those from CHV, give a better understanding of how slip is transferred into the complicated Mina defection to the east, from the dextral and normal faults along the Sierra Nevada Range front.

  5. Deformation associated with faulting within geologic and interseismic timescales

    NASA Astrophysics Data System (ADS)

    Marshall, Scott T.

    2008-04-01

    This dissertation consists of several distinct studies that use numerical modeling to better constrain deformation due to faulting over disparate timescales. Field mapping reveals a segment of the Lake Mead fault system, the Pinto Ridge fault, and a cluster of west-dipping normal faults located near Pinto Ridge. I suggest that this strike-slip segment was kinematically related to the Bitter Spring Valley fault, created the normal fault cluster at Pinto Ridge, and utilized these normal faults as linking structures between fault segments. Modeling results demonstrate that the location and orientations of the normal faults are consistent with having formed in the perturbed stress field around the slipping Pinto Ridge fault. Calculations of mechanical efficiency suggest that a preferred dip of normal faults in the region may reflect a crustal anisotropy at depth, such as a detachment. I present a methodology for simulating interseismic deformation in complex regions. I derive an analytical model of interseismic deformation that is equivalent to the conventional model. Based on this model, I formulate a two-step numerical simulation of geologic and interseismic deformation. I apply this technique to the Los Angeles region and find that model results match well both geologic slip rate estimates and geodetic velocities. Model results suggest that the Puente Hills thrusts are currently slipping at rates that are compatible with geologic estimates and that localized contraction in the San Gabriel basin is dominantly due to deep slip on the Sierra Madre fault. To assess the control of fault geometry and mechanical interactions on fault slip in a natural system, I create models of the Ventura region, California, using both planar and non-planar faults. I find that incorporating geologically-constrained fault surfaces into numerical models results in a better match to available geologic slip rate data than models utilizing planar faults. Because slip rates at most locations

  6. UAVSAR Indication of Right-Lateral Faults in Southern California

    NASA Astrophysics Data System (ADS)

    Donnellan, A.; Parker, J. W.

    2011-12-01

    UAVSAR data have been collected in southern California since spring of 2009. Data started being routinely collected in fall of 2009. Repeat pass interferometry (RPI) products show multiple lineations that strike SE parallel to the main strike of the San Andreas fault (outside of the Big bend). Aside from slip associated with the 2010 M 7.2 El Mayor Cucapah earthquake the lineations, while prominent in the data products, do not indicate large or any offsets on the faults. Faults that are indicated in the data include the Rialto-Colton fault, and the Superstition Hills fault. The RPI products indicate line of site changes between the ground and the instrument, which in this case is on an airborne platform. The flight lines were designed to be generally perpendicular to strike slip motions in southern California, and as a result should show the maximum component of motion toward the instrument. However, it is not possible to decompose horizontal versus vertical motions. Cross sections across these lineations show no offset, except near the 2010 El Mayor-Cucapah rupture, but show substantial differences in range change near the fault as compared to further from the fault. It is likely that different material properties within the fault zone, coupled with either ground-water migration or shaking from the El Mayor-Cucapah earthquake are the cause of these range change differences. We also discuss conjugate faulting associated with the 2010 earthquake and other crustal deformation observed in the Salton Trough.

  7. Water-rich bending faults at the Middle America Trench

    NASA Astrophysics Data System (ADS)

    Naif, Samer; Key, Kerry; Constable, Steven; Evans, Rob L.

    2015-09-01

    The portion of the Central American margin that encompasses Nicaragua is considered to represent an end-member system where multiple lines of evidence point to a substantial flux of subducted fluids. The seafloor spreading fabric of the incoming Cocos plate is oriented parallel to the trench such that flexural bending at the outer rise optimally reactivates a dense network of normal faults that extend several kilometers into the upper mantle. Bending faults are thought to provide fluid pathways that lead to serpentinization of the upper mantle. While geophysical anomalies detected beneath the outer rise have been interpreted as broad crustal and upper mantle hydration, no observational evidence exists to confirm that bending faults behave as fluid pathways. Here we use seafloor electromagnetic data collected across the Middle America Trench (MAT) offshore of Nicaragua to create a comprehensive electrical resistivity image that illuminates the infiltration of seawater along bending faults. We quantify porosity from the resistivity with Archie's law and find that our estimates for the abyssal plain oceanic crust are in good agreement with independent observations. As the Cocos crust traverses the outer rise, the porosity of the dikes and gabbros progressively increase from 2.7% and 0.7% to 4.8% and 1.7%, peaking within 20 km of the trench axis. We conclude that the intrusive crust subducts twice as much pore water as previously thought, significantly raising the flux of fluid to the seismogenic zone and the mantle wedge.

  8. Numerical modeling of shallow fault creep triggered by nearby earthquakes

    NASA Astrophysics Data System (ADS)

    Wei, M.; Liu, Y.; McGuire, J. J.

    2011-12-01

    The 2010 El Mayor-Cucapha Mw 7.2 earthquake is the largest earthquake that strikes southern California in the last 18 years. It has triggered shallow fault creep on many faults in Salton Trough, Southern California, making it at least the 8th time in the last 42 years that a local or regional earthquake has done so. However, the triggering mechanism of fault creep and its implications to seismic hazard and fault mechanics is still poorly understood. For example, what determines the relative importance of static triggering and dynamic triggering of fault creep? What can we learn about the local frictional properties and normal stress from the triggering of fault creep? To understand the triggering mechanism and constrain fault frictional properties, we simulate the triggered fault creep on the Superstition Hills Fault (SHF), Salton Trough, Southern California. We use realistic static and dynamic shaking due to nearby earthquakes as stress perturbations to a 2D (in a 3D medium) planar fault model with rate-and-state frictional property variations both in depth and along strike. Unlike many previous studies, we focus on the simulation of triggered shallow fault creep instead of earthquakes. Our fault model can reproduce the triggering process, by static, dynamic , and combined stress perturbation. Preliminary results show that the magnitude of perturbation relative to the original stress level is an important parameter. In the static case, perturbation of 1% of normal stress trigger delayed fault creep whereas 10% of normal stress generate instantaneous creep. In the dynamic case, a change of two times in magnitude of perturbation can result in difference of triggered creep in several orders of magnitude. We explore combined triggering with different ratio of static and dynamic perturbation. The timing of triggering in a earthquake cycle is also important. With measurements on triggered creep on the SHF, we constrain local stress level and frictional parameters, which

  9. Descent from the Summit of 'Husband Hill'

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Click on the image for Descent from the Summit of 'Husband Hill' (QTVR)

    In late November 2005 while descending 'Husband Hill,' NASA's Mars Exploration Rover Spirit took the most detailed panorama so far of the 'Inner Basin,' the rover's next target destination. Spirit acquired the 405 individual images that make up this 360-degree view of the surrounding terrain using five different filters on the panoramic camera. The rover took the images on Martian days, or sols, 672 to 677 (Nov. 23 to 28, 2005 -- the Thanksgiving holiday weekend).

    This image is an approximately true-color rendering using camera's 750-, 530-, and 430-nanometer filters. Seams between individual frames have been eliminated from the sky portion of the mosaic to better simulate the vista a person standing on Mars would see.

    'Home Plate,' a bright, semi-circular feature scientists hope to investigate, is harder to discern in this image than in earlier views taken from higher up the hill. Spirit acquired this more oblique view, known as the 'Seminole panorama,' from about halfway down the south flank of Husband Hill, 50 meters (164 feet) or so below the summit. Near the center of the panorama, on the horizon, are 'McCool Hill' and 'Ramon Hill,' named, like Husband Hill, in honor of the fallen astronauts of the space shuttle Columbia. Husband Hill is visible behind the rover, on the right and left sides of the panorama. An arc of rover tracks made while avoiding obstacles and getting into position to examine rock outcrops can be traced over a long distance by zooming in to explore the panorama in greater detail.

    Spirit is now significantly farther downhill toward the center of this panorama, en route to Home Plate and other enigmatic soils and outcrop rocks in the quest to uncover the history of Gusev Crater and the 'Columbia Hills.'

  10. A SYMPLECTIC INTEGRATOR FOR HILL'S EQUATIONS

    SciTech Connect

    Quinn, Thomas; Barnes, Rory; Perrine, Randall P.; Richardson, Derek C.

    2010-02-15

    Hill's equations are an approximation that is useful in a number of areas of astrophysics including planetary rings and planetesimal disks. We derive a symplectic method for integrating Hill's equations based on a generalized leapfrog. This method is implemented in the parallel N-body code, PKDGRAV, and tested on some simple orbits. The method demonstrates a lack of secular changes in orbital elements, making it a very useful technique for integrating Hill's equations over many dynamical times. Furthermore, the method allows for efficient collision searching using linear extrapolation of particle positions.

  11. Hill-Climbing Attacks and Robust Online Signature Verification Algorithm against Hill-Climbing Attacks

    NASA Astrophysics Data System (ADS)

    Muramatsu, Daigo

    Attacks using hill-climbing methods have been reported as a vulnerability of biometric authentication systems. In this paper, we propose a robust online signature verification algorithm against such attacks. Specifically, the attack considered in this paper is a hill-climbing forged data attack. Artificial forgeries are generated offline by using the hill-climbing method, and the forgeries are input to a target system to be attacked. In this paper, we analyze the menace of hill-climbing forged data attacks using six types of hill-climbing forged data and propose a robust algorithm by incorporating the hill-climbing method into an online signature verification algorithm. Experiments to evaluate the proposed system were performed using a public online signature database. The proposed algorithm showed improved performance against this kind of attack.

  12. Europa Ridges, Hills and Domes

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This moderate-resolution view of the surface of one of Jupiter's moons, Europa, shows the complex icy crust that has been extensively modified by fracturing and the formation of ridges. The ridge systems superficially resemble highway networks with overpasses, interchanges and junctions. From the relative position of the overlaps, it is possible to determine the age sequence for the ridge sets. For example, while the 8-kilometer-wide (5-mile) ridge set in the lower left corner is younger than most of the terrain seen in this picture, a narrow band cuts across the set toward the bottom of the picture, indicating that the band formed later. In turn, this band is cut by the narrow 2- kilometer-wide (1.2-mile) double ridge running from the lower right to upper left corner of the picture. Also visible are numerous clusters of hills and low domes as large as 9 kilometers (5.5 miles) across, many with associated dark patches of non-ice material. The ridges, hills and domes are considered to be ice-rich material derived from the subsurface. These are some of the youngest features seen on the surface of Europa and could represent geologically young eruptions.

    This area covers about 140 kilometers by 130 kilometers (87 miles by 81 miles) and is centered at 12.3 degrees north latitude, 268 degrees west longitude. Illumination is from the east (right side of picture). The resolution is about 180 meters (200 yards) per pixel, meaning that the smallest feature visible is about a city block in size. The picture was taken by the Solid State Imaging system on board the Galileo spacecraft on February 20, 1997, from a distance of 17,700 kilometers (11,000 miles) during its sixth orbit around Jupiter.

    The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington D.C. This image and other images and data received from Galileo are posted on the World Wide Web Galileo mission home page at http://galileo.jpl.nasa.gov.

  13. Threatened by mining, polymetallic nodules are required to preserve abyssal epifauna

    PubMed Central

    Vanreusel, Ann; Hilario, Ana; Ribeiro, Pedro A.; Menot, Lenaick; Arbizu, Pedro Martínez

    2016-01-01

    Polymetallic nodule mining at abyssal depths in the Clarion Clipperton Fracture Zone (Eastern Central Pacific) will impact one of the most remote and least known environments on Earth. Since vast areas are being targeted by concession holders for future mining, large-scale effects of these activities are expected. Hence, insight into the fauna associated with nodules is crucial to support effective environmental management. In this study video surveys were used to compare the epifauna from sites with contrasting nodule coverage in four license areas. Results showed that epifaunal densities are more than two times higher at dense nodule coverage (>25 versus ≤10 individuals per 100 m2), and that taxa such as alcyonacean and antipatharian corals are virtually absent from nodule-free areas. Furthermore, surveys conducted along tracks from trawling or experimental mining simulations up to 37 years old, suggest that the removal of epifauna is almost complete and that its full recovery is slow. By highlighting the importance of nodules for the epifaunal biodiversity of this abyssal area, we urge for cautious consideration of the criteria for determining future preservation zones. PMID:27245847

  14. Threatened by mining, polymetallic nodules are required to preserve abyssal epifauna.

    PubMed

    Vanreusel, Ann; Hilario, Ana; Ribeiro, Pedro A; Menot, Lenaick; Arbizu, Pedro Martínez

    2016-01-01

    Polymetallic nodule mining at abyssal depths in the Clarion Clipperton Fracture Zone (Eastern Central Pacific) will impact one of the most remote and least known environments on Earth. Since vast areas are being targeted by concession holders for future mining, large-scale effects of these activities are expected. Hence, insight into the fauna associated with nodules is crucial to support effective environmental management. In this study video surveys were used to compare the epifauna from sites with contrasting nodule coverage in four license areas. Results showed that epifaunal densities are more than two times higher at dense nodule coverage (>25 versus ≤10 individuals per 100 m(2)), and that taxa such as alcyonacean and antipatharian corals are virtually absent from nodule-free areas. Furthermore, surveys conducted along tracks from trawling or experimental mining simulations up to 37 years old, suggest that the removal of epifauna is almost complete and that its full recovery is slow. By highlighting the importance of nodules for the epifaunal biodiversity of this abyssal area, we urge for cautious consideration of the criteria for determining future preservation zones. PMID:27245847

  15. Threatened by mining, polymetallic nodules are required to preserve abyssal epifauna

    NASA Astrophysics Data System (ADS)

    Vanreusel, Ann; Hilario, Ana; Ribeiro, Pedro A.; Menot, Lenaick; Arbizu, Pedro Martínez

    2016-06-01

    Polymetallic nodule mining at abyssal depths in the Clarion Clipperton Fracture Zone (Eastern Central Pacific) will impact one of the most remote and least known environments on Earth. Since vast areas are being targeted by concession holders for future mining, large-scale effects of these activities are expected. Hence, insight into the fauna associated with nodules is crucial to support effective environmental management. In this study video surveys were used to compare the epifauna from sites with contrasting nodule coverage in four license areas. Results showed that epifaunal densities are more than two times higher at dense nodule coverage (>25 versus ≤10 individuals per 100 m2), and that taxa such as alcyonacean and antipatharian corals are virtually absent from nodule-free areas. Furthermore, surveys conducted along tracks from trawling or experimental mining simulations up to 37 years old, suggest that the removal of epifauna is almost complete and that its full recovery is slow. By highlighting the importance of nodules for the epifaunal biodiversity of this abyssal area, we urge for cautious consideration of the criteria for determining future preservation zones.

  16. Long-term change in benthopelagic fish abundance in the abyssal northeast Pacific Ocean.

    PubMed

    Bailey, D M; Ruhl, H A; Smith, K L

    2006-03-01

    Food web structure, particularly the relative importance of bottom-up and top-down control of animal abundances, is poorly known for the Earth's largest habitats: the abyssal plains. A unique 15-yr time series of climate, productivity, particulate flux, and abundance of primary consumers (primarily echinoderms) and secondary consumers (fish) was examined to elucidate the response of trophic levels to temporal variation in one another. Towed camera sled deployments in the abyssal northeast Pacific (4100 m water depth) showed that annual mean numbers of the dominant fish genus (Coryphaenoides spp.) more than doubled over the period 1989-2004. Coryphaenoides spp. abundance was significantly correlated with total abundance of mobile epibenthic megafauna (echinoderms), with changes in fish abundance lagging behind changes in the echinoderms. Direct correlations between surface climate and fish abundances, and particulate organic carbon (POC) flux and fish abundances, were insignificant, which may be related to the varied response of the potential prey taxa to climate and POC flux. This study provides a rare opportunity to study the long-term dynamics of an unexploited marine fish population and suggests a dominant role for bottom-up control in this system. PMID:16602284

  17. The absence of sharks from abyssal regions of the world's oceans.

    PubMed

    Priede, Imants G; Froese, Rainer; Bailey, David M; Bergstad, Odd Aksel; Collins, Martin A; Dyb, Jan Erik; Henriques, Camila; Jones, Emma G; King, Nicola

    2006-06-01

    The oceanic abyss (depths greater than 3000 m), one of the largest environments on the planet, is characterized by absence of solar light, high pressures and remoteness from surface food supply necessitating special molecular, physiological, behavioural and ecological adaptations of organisms that live there. Sampling by trawl, baited hooks and cameras we show that the Chondrichthyes (sharks, rays and chimaeras) are absent from, or very rare in this region. Analysis of a global data set shows a trend of rapid disappearance of chondrichthyan species with depth when compared with bony fishes. Sharks, apparently well adapted to life at high pressures are conspicuous on slopes down to 2000 m including scavenging at food falls such as dead whales. We propose that they are excluded from the abyss by high-energy demand, including an oil-rich liver for buoyancy, which cannot be sustained in extreme oligotrophic conditions. Sharks are apparently confined to ca 30% of the total ocean and distribution of many species is fragmented around sea mounts, ocean ridges and ocean margins. All populations are therefore within reach of human fisheries, and there is no hidden reserve of chondrichthyan biomass or biodiversity in the deep sea. Sharks may be more vulnerable to over-exploitation than previously thought. PMID:16777734

  18. The absence of sharks from abyssal regions of the world's oceans

    PubMed Central

    Priede, Imants G; Froese, Rainer; Bailey, David M; Bergstad, Odd Aksel; Collins, Martin A; Dyb, Jan Erik; Henriques, Camila; Jones, Emma G; King, Nicola

    2006-01-01

    The oceanic abyss (depths greater than 3000 m), one of the largest environments on the planet, is characterized by absence of solar light, high pressures and remoteness from surface food supply necessitating special molecular, physiological, behavioural and ecological adaptations of organisms that live there. Sampling by trawl, baited hooks and cameras we show that the Chondrichthyes (sharks, rays and chimaeras) are absent from, or very rare in this region. Analysis of a global data set shows a trend of rapid disappearance of chondrichthyan species with depth when compared with bony fishes. Sharks, apparently well adapted to life at high pressures are conspicuous on slopes down to 2000 m including scavenging at food falls such as dead whales. We propose that they are excluded from the abyss by high-energy demand, including an oil-rich liver for buoyancy, which cannot be sustained in extreme oligotrophic conditions. Sharks are apparently confined to ca 30% of the total ocean and distribution of many species is fragmented around sea mounts, ocean ridges and ocean margins. All populations are therefore within reach of human fisheries, and there is no hidden reserve of chondrichthyan biomass or biodiversity in the deep sea. Sharks may be more vulnerable to over-exploitation than previously thought. PMID:16777734

  19. Analysis of the community structure of abyssal kinetoplastids revealed similar communities at larger spatial scales

    PubMed Central

    Salani, Faezeh Shah; Arndt, Hartmut; Hausmann, Klaus; Nitsche, Frank; Scheckenbach, Frank

    2012-01-01

    Knowledge of the spatial scales of diversity is necessary to evaluate the mechanisms driving biodiversity and biogeography in the vast but poorly understood deep sea. The community structure of kinetoplastids, an important group of microbial eukaryotes belonging to the Euglenozoa, from all abyssal plains of the South Atlantic and two areas of the eastern Mediterranean was studied using partial small subunit ribosomal DNA gene clone libraries. A total of 1364 clones from 10 different regions were retrieved. The analysis revealed statistically not distinguishable communities from both the South-East Atlantic (Angola and Guinea Basin) and the South-West Atlantic (Angola and Brazil Basin) at spatial scales of 1000–3000 km, whereas all other communities were significantly differentiated from one another. It seems likely that multiple processes operate at the same time to shape communities of deep-sea kinetoplastids. Nevertheless, constant and homogenous environmental conditions over large spatial scales at abyssal depths, together with high dispersal capabilities of microbial eukaryotes, maintain best the results of statistically indistinguishable communities at larger spatial scales. PMID:22071346

  20. Evidence for deep-water deposition of abyssal Mediterranean evaporites during the Messinian salinity crisis

    NASA Astrophysics Data System (ADS)

    Christeleit, Elizabeth C.; Brandon, Mark T.; Zhuang, Guangsheng

    2015-10-01

    Scientific drilling of the abyssal evaporites beneath the deepest parts of the Mediterranean basin gave rise to the idea that the Mediterranean sea completely evaporated at the end of the Messinian. Herein, we show, using new organic geochemical data, that those evaporites were deposited beneath a deep-water saline basin, not in a subaerial saltpan, as originally proposed. Abundant fossil organic lipids were extracted from evaporites in Mediterranean Deep Sea Drilling Project cores. The archaeal lipid distribution and new analyses, using the ACE salinity proxy and TEX86 temperature proxy, indicate that surface waters at the time of evaporite deposition had normal marine salinity, ranging from ∼26 to 34 practical salinity units, and temperatures of 25-28 °C. These conditions require a deep-water setting, with a mixed layer with normal marine salinity and an underlying brine layer at gypsum and halite saturation. After correction for isostatic rebound, our results indicate maximum drawdown of ∼2000 m and ∼2900 m relative to modern sea level in the western and eastern Mediterranean basins, respectively. Our results are consistent with previously proposed scenarios for sea level drawdown based on both subaerial and submarine incision and backfilling of the Rhone and Nile rivers, which require Messinian sea level drops of ∼1300 m and ∼200 m, respectively. This study provides new evidence for an old debate and also demonstrates the importance of further scientific drilling and sampling of deeper part of the abyssal Messinian units.

  1. The Gulf Stream pathway and the impacts of the eddy-driven abyssal circulation and the Deep Western Boundary Current

    NASA Astrophysics Data System (ADS)

    Hurlburt, Harley E.; Hogan, Patrick J.

    2008-08-01

    A hydrodynamic model of the subtropical Atlantic basin and the Intra-Americas Sea (9-47°N) is used to investigate the dynamics of Gulf Stream separation from the western boundary at Cape Hatteras and its mean pathway to the Grand Banks. The model has five isopycnal Lagrangian layers in the vertical and allows realistic boundary geometry, bathymetry, wind forcing, and a meridional overturning circulation (MOC), the latter specified via ports in the northern and southern boundaries. The northward upper ocean branch of the MOC (14 Sv) was always included but the southward Deep Western Boundary Current (DWBC) was excluded in some simulations, allowing investigation of the impacts of the DWBC and the eddy-driven mean abyssal circulation on Gulf Stream separation from the western boundary. The result is resolution dependent with the DWBC playing a crucial role in Gulf Stream separation at 1/16° resolution but with the eddy-driven abyssal circulation alone sufficient to obtain accurate separation at 1/32° resolution and a realistic pathway from Cape Hatteras to the Grand Banks with minimal DWBC impact except southeast of the Grand Banks. The separation from the western boundary is particularly sensitive to the strength of the eddy-driven abyssal circulation. Farther to the east, between 68°W and the Grand Banks, all of the 1/16° and 1/32° simulations with realistic topography (with or without a DWBC) gave similar generally realistic mean pathways with clear impacts of the topographically constrained eddy-driven abyssal circulation versus very unrealistic Gulf Stream pathways between Cape Hatteras and the Grand Banks from otherwise identical simulations run with a flat bottom, in reduced-gravity mode, or with 1/8° resolution and realistic topography. The model is realistic enough to allow detailed model-data comparisons and a detailed investigation of Gulf Stream dynamics. The corresponding linear solution with a Sverdrup interior and Munk viscous western boundary

  2. Major Elements Budget Between Abyssal Peridotite And Seawater During The Serpentinization

    NASA Astrophysics Data System (ADS)

    Yu, X.; Dong, Y.; Li, X.; Chu, F.

    2012-12-01

    Water-Rock Interaction is one of the most hot-debated issues among geologists, geophysicists, as well as geochemists. Abyssal peridotites recovered from the seafloor are often greatly affected or alterated by seawater in the form of serpentinization. The alteration to the peridotites makes it difficult to do the straightforward analysis for its primary composition as it was settled in the upper mantle, which confine the usage of these rare direct samples from the mantle in the scientific study, such as mantle dynamics, mantle composition and crust-mantle interaction. Besides, It was revealed recently that the serpentinization of abyssal peridotites may give birth to the hydrothermal activity. The elements migration during the serpentinization may perform a great role on the chemical composition of the hydrothermal fluid, which can support a hidden chemosynthetic ecosystem in the abyssal seabed. The research work focused on the major elements behavior during the serpentinization by studying the partially serpentinized samples of abyssal peridotite from Southwest Indian Ridge. The primary mineral assemblage of peridotite is olivine (Mg2SiO4), orthopyroxene (Mg2Si2O6), clinopyroxene (CaMgSi2O6) and spinel ((Mg,Fe)(Al,Cr)2O4). The major chemical composition are usually as SiO2 (30~45wt.%), MgO (20~45 wt.%), FeO and Fe2O3 (total 5~15 wt.%). Besides there are very few MnO, CaO, Al2O3, Cr2O3, NiO, Na2O, K2O and H2O. While on the other hand the serpentinized peridotite shows a more complicated mineral assemblage, besides the primary minerals there are more alteration minerals, such as serpentine (Mg3[Si2O5](OH)4), magnetite (Fe3O4), talc (Mg3[Si4O10](OH)2), brucite (Mg(OH)2), tremolite (Ca2Mg5[Si8O22](OH)2), chromite (FeCr2O4), chlorite ((Mg,Fe)6[(Si,Al)4O10](OH)8), and other accessary minerals like native metals, sulfides, clay minerals and hornblende. According to the EMPA analysis, the serpentinized sample shows the chemical composition as SiO2(~40 wt.%), MgO(~30 wt

  3. Element partitioning and thermal-compositional patterns in coexisting muscovites and biotites, Black Hills, SD

    SciTech Connect

    Dahl, P.S.; Feldman, S.G.; Wehn, D.C. . Dept. of Geology)

    1992-01-01

    Twenty-two elements in 50 coexisting muscovites and biotites from pelitic schists of the southern Black Hills have been analyzed by ICP spectrometry. Most elements exhibit highly systematic partitioning between the micas over a wide range of composition. Sillimanite-zone micas are typically enriched in K, Ti, and Li but depleted in Na relative to those from the staurolite zone. Also, sillimanite-zone biotites are relatively depleted in Mg/(Fe+Mg), but enriched in Mn, relative to those of the staurolite zone. Preliminary verification of the muscovite-biotite thermometer (calibration of Hoish (1989)) is indicated from a regional thermal pattern that is strikingly similar to that obtained by Friberg et al. (in prep.) using garnet (rim) - biotite thermometry. The lowest K/(Na+K)[sup mus], X[sub Li] (bio), mica temperatures, and highest X[sub Mg](bio) in the region are observed in staurolite-zone schists between the Grand Junction and Hill City Faults. These regional patterns correlate with: (1) mapped gravity lows (subsurface granitic plutons ), (2) mapped pegmatite density, and (3) proximity to the main mass of Harney Peak Granite. As such, pelitic micas appear to record the T-X signatures of vertically( )-flowing alkali metasomatic fluids that variably overprinted low- to medium-grade regional-metamorphic assemblages during emplacement of the Harney Peak granite-pegmatite complex. The area between the Grand Junction and Hill City faults appears least affected by the metasomatic activity associated with this magmatic event.

  4. Buried-hill discoveries in Damintan depression of north China basin

    SciTech Connect

    Xiaoguang, Tong; Huang Zuan

    1988-02-01

    The Damintan fault depression is about 20 km west of Shenyang, Liaoning Province, North China, and is a small Tertiary continental depression, covering only about 800 km/sup 2/. In the depression, the Tertiary system unconformably overlies upper-middle Proterozoic sedimentary rocks and Archean metamorphic rocks. The Tertiary system is up to 6,600 m in thickness. Source rocks are in the third and fourth members of the Eocene Shahejie Formation. Buried-hill traps were formed in Proterozoic carbonates and metamorphic rocks of the Archean. Fault block, stratigraphic, and lithologic traps also occur in sandstones of the Shahejie Formation, especially in those of the third member. Several buried-hill-drape traps occur in the depression. The various types of oil pools in each buried-hill-drape trap constitute a complex hydrocarbon accumulation zone. A series of oil fields have been found in the depression. The crude oil is characterized by high wax content and high pour point. Hydrocarbon exploration began in 1971, but only a few small oil fields were found in the 1970s. Recently, by applying digital seismic techniques, the subsurface geological structure has been accurately mapped and new production technology has enabled the high-our-point oil to be produced. Thus, important achievements in hydrocarbon exploration were made during the 1980s.

  5. New slip rate estimates for the Mission Creek strand of the San Andreas fault zone

    NASA Astrophysics Data System (ADS)

    Blisniuk, K.; Scharer, K. M.; Sharp, W. D.; Burgmann, R.; Rymer, M. J.; Williams, P. L.

    2013-12-01

    The potential for a large-magnitude earthquake (Mw ≥ 6.7) on the southern San Andreas fault zone (SAFZ) is generally considered high (Working Group on California Earthquake Probabilities, 2007). However, the proportion of slip accommodated by each of its three major fault strands (Mission Creek, Banning, and Garnet Hill, from north to south) in the Indio Hills is poorly constrained. Each of these strands cut through San Gorgonio Pass west to the Los Angeles metropolitan region. To better assess the relative importance of these faults and their potential for a major earthquake, we dated offsets at two sites on the Mission Creek fault in the central Indio Hills, an offset channel at Pushawalla Canyon and an offset debris cone at a small unnamed canyon located ~1.5 km farther southeast. Previous work on this strand at Biskra Palms, in the southern Indio Hills, demonstrated a slip rate between 12 and 22 mm/yr, with a preferred rate of 14-17 mm/yr (Behr et al., GSAB, 2010). It is generally assumed that the slip rate on the Mission Creek fault decreases northwestwards from Biskra Palms (e.g. Fumal et al., BSSA, 2002) towards these two sites in the central Indio Hills. However, our initial results from uranium-series dating of pedogenic carbonate and 10Be cosmogenic exposure dating of surface clasts from deposits offset 1.3-1.6 km since ~70 ka and 44-50 m since ~2.5 ka indicate that during the late Pleistocene and Holocene slip on the Mission Creek fault in the central Indio Hills has occurred at a relatively constant and unexpectedly high rate of ~20 mm/yr. Combined with published paleoseismic studies for the Mission Creek fault, which show an average earthquake recurrence interval of 225 years for the past 5 events since 900 AD (Fumal et al., 2002), these data imply an average slip-per-event of ~4.5 m. The last earthquake to rupture this section of the Mission Creek fault occurred over 300 years ago (ca. 1690), which indicates that ca. 5.0 to 7.5 m of strain may have

  6. Inside Beacon Hill: Bertrand Russell as Schoolmaster.

    ERIC Educational Resources Information Center

    Jespersen, Shirley

    1987-01-01

    The author describes the life and theories of Bertrand Russell, founder of Beacon Hill School. Russell's educational theories centered on the personal autonomy of the student and democratization of the learning process. (CH)

  7. Exploring Hill Ciphers with Graphing Calculators.

    ERIC Educational Resources Information Center

    St. John, Dennis

    1998-01-01

    Explains how to code and decode messages using Hill ciphers which combine matrix multiplication and modular arithmetic. Discusses how a graphing calculator can facilitate the matrix and modular arithmetic used in the coding and decoding procedures. (ASK)

  8. Fault slip distribution and fault roughness

    NASA Astrophysics Data System (ADS)

    Candela, Thibault; Renard, François; Schmittbuhl, Jean; Bouchon, Michel; Brodsky, Emily E.

    2011-11-01

    We present analysis of the spatial correlations of seismological slip maps and fault topography roughness, illuminating their identical self-affine exponent. Though the complexity of the coseismic spatial slip distribution can be intuitively associated with geometrical or stress heterogeneities along the fault surface, this has never been demonstrated. Based on new measurements of fault surface topography and on statistical analyses of kinematic inversions of slip maps, we propose a model, which quantitatively characterizes the link between slip distribution and fault surface roughness. Our approach can be divided into two complementary steps: (i) Using a numerical computation, we estimate the influence of fault roughness on the frictional strength (pre-stress). We model a fault as a rough interface where elastic asperities are squeezed. The Hurst exponent ?, characterizing the self-affinity of the frictional strength field, approaches ?, where ? is the roughness exponent of the fault surface in the direction of slip. (ii) Using a quasi-static model of fault propagation, which includes the effect of long-range elastic interactions and spatial correlations in the frictional strength, the spatial slip correlation is observed to scale as ?, where ? represents the Hurst exponent of the slip distribution. Under the assumption that the origin of the spatial fluctuations in frictional strength along faults is the elastic squeeze of fault asperities, we show that self-affine geometrical properties of fault surface roughness control slip correlations and that ?. Given that ? for a wide range of faults (various accumulated displacement, host rock and slip movement), we predict that ?. Even if our quasi-static fault model is more relevant for creeping faults, the spatial slip correlations observed are consistent with those of seismological slip maps. A consequence is that the self-affinity property of slip roughness may be explained by fault geometry without considering

  9. The Igwisi Hills extrusive 'kimberlites'

    NASA Technical Reports Server (NTRS)

    Reid, A. M.; Donaldson, C. H.; Dawson, J. B.; Brown, R. W.; Ridley, W. I.

    1975-01-01

    The petrography and mineral chemistry of volcanic rocks from the Igwisi Hills in Tanzania are discussed. There is considerable evidence to suggest that the Igwisi rocks are extrusive kimberlites: a two-component nature with high P-T minerals in a low P-T matrix; the presence of chrome pyrope, Al enstatite, chrome diopside, chromite and olivine; a highly oxidized, volatile-rich matrix with serpentine, calcite, magnetite, perovskite; high Sr, Zr, and Nb contents; occurrence in a narrow isolated vent within a stable shield area. The Igwisi rocks differ from kimberlite in the lack of magnesian ilmenite, the scarcity of matrix phlogopite, and the overall low alkali content. They apparently contain material from phlogopite-bearing garnet peridotites with a primary mineral assemblage indicative of equilibrium at upper mantle temperatures and pressures. This primary assemblage was brought rapidly to the surface in a gas-charged, carbonate-rich fluid. Rapid upward transport, extrusion, and rapid cooling have tended to prevent reaction between inclusions and the carbonate-rich matrix that might otherwise have yielded a more typical kimberlite.

  10. Oblique View of Columbia Hills

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Annotated Version

    This perspective view looking toward the northeast shows part of the Columbia Hills range inside Gusev Crater. At the center is the winter campaign site of NASA's Mars Exploration Rover Spirit.

    On its 805th Martian day, or sol, (April 8, 2006), Spirit was parked on a slope tilting 11 degrees to the north to maximize sunlight on the solar panels during the southern winter season. Science observations were formulated to take advantage of the long time during which the rover was parked. The plan focused on two tasks: tracking atmospheric and surface dynamics by periodically surveying the surface and atmosphere; and extensively examining surrounding terrains, rocks and soils using the panoramic camera and the miniature thermal emission spectrometer, coupled with long duration measurements using the alpha particle X-ray and Moessbauer spectrometers of rock and soil targets. For reference, the feature known as 'Home Plate' is approximately 90 meters (295 feet) wide.

    An image from Mars Global Surveyor's Mars Orbital Camera, catalogued as E03_00012 and courtesy Malin Space Science Systems, was used as the base image for this figure. The perspective was generated using elevation data generated from analyses of the camera's stereo images by the U.S. Geological Survey, Flagstaff, Ariz.

  11. Soufriere Hills, Montserrat, West Indies

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Volcanic activity on the West Indian island of Montserrat has remained high for several years-the current activity started in 1995. However, remote sensing of the island has been difficult because of frequent cloud cover. The International Space Station crew flew north of the island on a clear day in early July (July 9, 2001) and recorded a vigorous steam plume emanating from the summit of Soufriere Hills. The image also reveals the extensive volcanic mud flows (lahars) and new deltas built out from the coast from the large amounts of volcanic debris delivered downstream by the rivers draining the mountain. As a small island (only 13 x 8 km), all of Montserrat has been impacted by the eruptions. Sources of Information: Smithsonian Global Volcanism Program Italy's Volcanoes Montserrat Volcano Observatory Digital photograph number ISS002-E-9309 was taken on 9 July 2001 from Space Station Alpha and was provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

  12. Secondary Normal Faulting Near the Terminus of a Strike-Slip Fault Segment in the Lake Mead Fault System, SE Nevada

    NASA Astrophysics Data System (ADS)

    Marshall, S. T.; Kattenhorn, S. A.

    2003-12-01

    The 95 km long Lake Mead Fault System (LMFS), located about 50 km east of Las Vegas and about 100 km west of the relatively undeformed Colorado Plateau, consists of a group of NE/SW-trending Miocene left-lateral strike-slip faults with a total offset of 65-110 km. Previous work suggests that the LMFS acted as a transform zone to accommodate differential extension between the southern Basin and Range to the north and the metamorphic core complexes of the Colorado River extensional corridor to the south. Studies of individual faults of the LMFS have shown that strike-slip faulting was the dominant mode of deformation while normal faulting, pull-apart basins, and push up structures formed as localized secondary structures related to strike-slip faults. This study focuses on the portion of the LMFS west of the Overton Arm of Lake Mead, which consists of the Bitter Spring Valley Fault (BSVF) and the Hamblin Bay Fault (HBF). Both faults have estimated offsets of 20-60 km, but past mapping efforts have been inconsistent with respect to the BSVF trace locations and degree of fault complexity. In order to demonstrate that the apparent complexity of the BSVF is the result of segmentation and secondary normal faults associated with individual segments, we focused field mapping efforts on an apparent segment of the BSVF near Pinto Ridge, located southwest of the Echo Hills and about 5 km NW of the more prominent HBF. We have identified nine normal faults that initiate near the SW tip of a segment of the BSVF and die out to the south before reaching the HBF. The offset on all these faults is a maximum at their northern intersection with the BSVF, then steadily decreases to zero away from the BSVF. These normal faults range from 0.6 km-2.25 km in length and have variable fault trace patterns. The normal fault originating closest to the SW tip of the BSVF segment curves with increasing distance away towards parallelism with the BSVF. The eight other normal faults are all oriented

  13. Flight elements: Fault detection and fault management

    NASA Technical Reports Server (NTRS)

    Lum, H.; Patterson-Hine, A.; Edge, J. T.; Lawler, D.

    1990-01-01

    Fault management for an intelligent computational system must be developed using a top down integrated engineering approach. An approach proposed includes integrating the overall environment involving sensors and their associated data; design knowledge capture; operations; fault detection, identification, and reconfiguration; testability; causal models including digraph matrix analysis; and overall performance impacts on the hardware and software architecture. Implementation of the concept to achieve a real time intelligent fault detection and management system will be accomplished via the implementation of several objectives, which are: Development of fault tolerant/FDIR requirement and specification from a systems level which will carry through from conceptual design through implementation and mission operations; Implementation of monitoring, diagnosis, and reconfiguration at all system levels providing fault isolation and system integration; Optimize system operations to manage degraded system performance through system integration; and Lower development and operations costs through the implementation of an intelligent real time fault detection and fault management system and an information management system.

  14. Aspects of the earthquake geology and seismotectonics of the southern San Andreas and related faults

    NASA Astrophysics Data System (ADS)

    Williams, Patrick Lee

    Aspects of the mechanics and movement history of the southernmost San Andreas or related faults are addressed. The seismotectonic context of the southernmost San Andreas fault is investigated. Microstratigraphic and geomorphological investigations of the fault's segmentation, slip potential and latest seismogenic slip history are presented. Measurements of geological deposits, man-made structures, alignment arrays and creepmeters offset across the southernmost San Andreas fault are presented. These measure the fault's aseismic slip rate during the past three hundred years. Observations of triggered aseismic slippage along the southernmost 100 km of the San Andreas fault soon after the North Palm Springs earthquake are described. Dextral surficial slip ranging from less than or equal to 9 mm and occurred on three sections of the San Andreas fault that lie between 44 and 86 km from the epicenter near North Palm Springs. Data complied and interpretations gleaned from repeated measurements of surface slip at dozens of site along the Superstition Hills fault during the period of two hours to one year after the Superstition Hills earthquake are presented. The common result of these five investigations is increased understanding of phenomena associated with fault motion along the highly active border between the Pacific and North American plates.

  15. Fault damage zones

    NASA Astrophysics Data System (ADS)

    Kim, Young-Seog; Peacock, David C. P.; Sanderson, David J.

    2004-03-01

    Damage zones show very similar geometries across a wide range of scales and fault types, including strike-slip, normal and thrust faults. We use a geometric classification of damage zones into tip-, wall-, and linking-damage zones, based on their location around faults. These classes can be sub-divided in terms of fault and fracture patterns within the damage zone. A variety of damage zone structures can occur at mode II tips of strike-slip faults, including wing cracks, horsetail fractures, antithetic faults, and synthetic branch faults. Wall damage zones result from the propagation of mode II and mode III fault tips through a rock, or from damage associated with the increase in slip on a fault. Wall damage zone structures include extension fractures, antithetic faults, synthetic faults, and rotated blocks with associated triangular openings. The damage formed at the mode III tips of strike-slip faults (e.g. observed in cliff sections) are classified as wall damage zones, because the damage zone structures are distributed along a fault trace in map view. Mixed-mode tips are likely to show characteristics of both mode II and mode III tips. Linking damage zones are developed at steps between two sub-parallel faults, and the structures developed depend on whether the step is extensional or contractional. Extension fractures and pull-aparts typically develop in extensional steps, whilst solution seams, antithetic faults and synthetic faults commonly develop in contractional steps. Rotated blocks, isolated lenses or strike-slip duplexes may occur in both extensional and contractional steps. Damage zone geometries and structures are strongly controlled by the location around a fault, the slip mode at a fault tip, and by the evolutionary stage of the fault. Although other factors control the nature of damage zones (e.g. lithology, rheology and stress system), the three-dimensional fault geometry and slip mode at each tip must be considered to gain an understanding of

  16. Is there a "blind" strike-slip fault at the southern end of the San Jacinto Fault system?

    NASA Astrophysics Data System (ADS)

    Tymofyeyeva, E.; Fialko, Y. A.

    2015-12-01

    We have studied the interseismic deformation at the southern end of the San Jacinto fault system using Interferometric Synthetic Aperture Radar (InSAR) and Global Positioning System (GPS) data. To complement the continuous GPS measurements from the PBO network, we have conducted campaign-style GPS surveys of 19 benchmarks along Highway 78 in the years 2012, 2013, and 2014. We processed the campaign GPS data using GAMIT to obtain horizontal velocities. The data show high velocity gradients East of the surface trace of the Coyote Creek Fault. We also processed InSAR data from the ascending and descending tracks of the ENVISAT mission between the years 2003 and 2010. The InSAR data were corrected for atmospheric artifacts using an iterative common point stacking method. We combined average velocities from different look angles to isolate the fault-parallel velocity field, and used fault-parallel velocities to compute strain rate. We filtered the data over a range of wavelengths prior to numerical differentiation, to reduce the effects of noise and to investigate both shallow and deep sources of deformation. At spatial wavelengths less than 2km the strain rate data show prominent anomalies along the San Andreas and Superstition Hills faults, where shallow creep has been documented by previous studies. Similar anomalies are also observed along parts of the Coyote Creek Fault, San Felipe Fault, and an unmapped southern continuation of the Clark strand of the San Jacinto Fault. At wavelengths on the order of 20km, we observe elevated strain rates concentrated east of the Coyote Creek Fault. The long-wavelength strain anomaly east of the Coyote Creek Fault, and the localized shallow creep observed in the short-wavelength strain rate data over the same area suggest that there may be a "blind" segment of the Clark Fault that accommodates a significant portion of the deformation on the southern end of the San Jacinto Fault.

  17. Expression of San Andreas fault on Seasat radar image

    NASA Technical Reports Server (NTRS)

    Sabins, F. F., Jr.; Blom, R.; Elachi, C.

    1980-01-01

    A Seasat image (23.5 cm wavelength) of the Durmid Hills in southern California, the San Andreas Fault was analyzed. It is shown that a prominent southeast trending tonal lineament exists that is bright on the southwest side and dark on the northeast side. The cause of the contrasting signatures on opposite sides of the lineament was determined and the geologic signficance of the lineament was evaluated.

  18. Triggered Fault Slip in Southern California Associated with the 2010 Sierra El Mayor-Cucapah, Baja California, Mexico, Earthquake

    NASA Astrophysics Data System (ADS)

    Rymer, M. J.; Treiman, J. A.; Kendrick, K. J.; Lienkaemper, J. J.; Wei, M.; Weldon, R. J.; Bilham, R. G.; Fielding, E. J.

    2010-12-01

    Surface fracturing (triggered slip) occurred in the central Salton Trough and to the southwest, in the Yuha Desert area—all in association with the 4 April 2010 (M7.2) El Mayor-Cucapah earthquake and its aftershocks. Triggered slip in the central Salton Trough occurred on the ‘frequent movers’: the southern San Andreas, Coyote Creek, Superstition Hills, and Imperial Faults, all of which have slipped in previous moderate to large, local and regional earthquakes in the past five decades. Other faults in the central Salton Trough that also slipped in 2010 include the Wienert Fault (southeastern section of the Superstition Hills Fault), the Kalin Fault (in the Brawley Seismic Zone), and the Brawley Fault Zone; triggered slip had not been reported on these faults in the past. Geologic measures of slip on faults in the central Salton Trough ranged from 1 to 18 mm, and everywhere was located where previous primary (tectonic) or triggered slip has occurred. Triggered slip in the Yuha Desert area occurred along at least two dozen faults, only some of which were known before the 4 April 2010 El Mayor-Cucapah earthquake. From east to northwest, slip occurred in seven general areas; 1) in the Northern Centinela Fault Zone (newly named), 2) along unnamed faults south of Pinto Wash, 3) along the Yuha Fault (newly named), 4) along both east and west branches of the Laguna Salada Fault, 5) along the Yuha Well Fault Zone (newly revised name), 6) along the Ocotillo Fault (newly named), and 7) along the southeastern-most section of the Elsinore Fault. Faults that slipped in the Yuha Desert area include northwest-trending right-lateral faults, northeast-trending left-lateral faults, and north-south faults, some of which had dominantly vertical slip. Triggered slip along the Ocotillo and Elsinore Faults occurred only in association with the 14 June 2010 (M5.7) aftershock, which also initiated slip along other faults near the town of Ocotillo. Triggered slip on faults in the Yuha

  19. Drought in the Black Hills

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Annotated Color-Coded Map

    Despite good rainfall and record-setting snowstorms in the spring of 2005, most of northeastern Wyoming, the Black Hills, and western South Dakota remain in the midst of a severe drought. This set of images and maps from NASA's Multi-angle Imaging SpectroRadiometer (MISR) contrast the appearance of the Black Hills region of northwestern South Dakota on July 12, 2000 (left column), with views acquired four years later, on July 14, 2004 (right column). The natural-color images along the top are from MISR's nadir (downward-looking) camera. The browning that appears in 2004 compared with 2000 indicates that the vigor of green vegetation was significantly diminished in 2004.

    The color-coded maps (along the bottom) provide a quantitative measurement of the sunlight reflected from these surfaces, and the loss of sunlight-absorbing vegetation between the 2000 and 2004 dates. As the vegetation faded with the drought, the albedo at the surface increased. Albedo measures the fraction of incident sunlight that is reflected by a surface, and can vary between zero (if all the incident sunlight is absorbed and none is reflected) and one (if all sunlight is reflected and none is absorbed). Dense forest has a low albedo; bright desert, snow and clouds, have a high albedo. Here, albedo is provided for the wavelengths of sunlight that plants use for photosynthesis (400 - 700 nanometers). This measurement is known as the albedo for Photosynthetically Active Radiation (PAR). Surfaces with greater absorption of PAR appear here in blue hues, whereas surfaces with lower absorption appear as green, yellow, orange or red. Black pixels indicate areas where albedo could not be derived, usually due to the presence of clouds. In July 2004, low albedo areas (blue pixels) are notably reduced in extent, and higher albedo areas (yellow, orange and red pixels) have increased.

    Because incoming sunlight is

  20. Bunker Hill Sediment Characterization Study

    SciTech Connect

    Neal A. Yancey; Debby F. Bruhn

    2009-12-01

    The long history of mineral extraction in the Coeur d’Alene Basin has left a legacy of heavy metal laden mine tailings that have accumulated along the Coeur d’Alene River and its tributaries (U.S. Environmental Protection Agency, 2001; Barton, 2002). Silver, lead and zinc were the primary metals of economic interest in the area, but the ores contained other elements that have become environmental hazards including zinc, cadmium, lead, arsenic, nickel, and copper. The metals have contaminated the water and sediments of Lake Coeur d’Alene, and continue to be transported downstream to Spokane Washington via the Spokane River. In 1983, the EPA listed the Bunker Hill Mining and Metallurgical Complex on the National Priorities List. Since that time, many of the most contaminated areas have been stabilized or isolated, however metal contaminants continue to migrate through the basin. Designation as a Superfund site causes significant problems for the economically depressed communities in the area. Identification of primary sources of contamination can help set priorities for cleanup and cleanup options, which can include source removal, water treatment or no action depending on knowledge about the mobility of contaminants relative to water flow. The mobility of contaminant mobility under natural or engineered conditions depends on multiple factors including the physical and chemical state (or speciation) of metals and the range of processes, some of which can be seasonal, that cause mobilization of metals. As a result, it is particularly important to understand metal speciation (National Research Council, 2005) and the link between speciation and the rates of metal migration and the impact of natural or engineered variations in flow, biological activity or water chemistry.

  1. Identification of active faults in enlarged stereo models of Skylab S-190B photographs

    NASA Technical Reports Server (NTRS)

    Merifield, P. M.

    1983-01-01

    Most of the physiographic indicators of recent movement known to be present along the Indio Hills segment of the San Andreas fault zone can be identified on enlarged Skylab S-190B stereo photographs. These include offset streams, beheaded streams, offset fans, shutter ridges, linear valleys, scarps and vegetation anomalies. Where physiographic indicators of recent movement are present, the S-190B system affords the necessary resolution and stereoscopy for distinguishing activate from inactive faults.

  2. Implications of spinel compositions for the petrotectonic history of abyssal peridotite from Southwest Indian Ridge (SWIR)

    NASA Astrophysics Data System (ADS)

    Chen, T.; Jin, Z.; Wang, Y.; Tao, C.

    2012-12-01

    Abyssal peridotites generate at mid-ocean ridges. Lherzolite and harzburgite are the main rock types of peridotites in the uppermost mantle. The lherzolite subtype, less depleted and less common in ophiolites, characterizes mantle diapirs and slow-spreading ridges. Along the Earth's mid-ocean ridges, abyssal peridotites undergo hydration reactions to become serpentinite minerals, especially in slow to ultraslow spreading mid-ocean ridges. Spinel is common in small quantities in peridotites, and its compositions have often been used as petrogenetic indicators [1]. The Southwest Indian Ridge (SWIR) is one of the two ultraslow spreading ridges in the world. The studied serpentinized peridotite sample was collected by the 21st Voyage of the Chinese oceanic research ship Dayang Yihao (aka Ocean No. 1) from a hydrothermal field (63.5°E, 28.0°S, and 3660 m deep) in SWIR. The studied spinels in serpentinized lherzolite have four zones with different compositions: relic, unaltered core is magmatic Al-spinels; micro- to nano- sized ferrichromite zoned particles; narrow and discontinuous magnetite rim; and chlorite aureoles. The values Cr# of the primary Al-spinels indicate the range of melting for abyssal peridotites from SWIR extends from ~4% to ~7% [2]. The alteration rims of ferrichromite have a chemical composition characterized by Fe enrichment and Cr# increase indicating chromite altered under greenschist-amphibolite facies. Magnetites formed in syn- and post- serpentinization. Chlorite (clinochlore) formed at the boundary and crack of spinel indicating it had undergone with low-temperature MgO- and SiO2-rich hydrothermal fluids [3]. It suggests that serpentinized lherzolite from SWIR had undergone poly-stage hydration reactions with a wide range of temperature. Acknowledgments: EMPA experiment was carried out by Xihao Zhu and Shu Zheng in The Second Institute of Oceanography and China University of Geosciences, respectively. The work was supported by NSFC

  3. Seafloor Mapping of the Southeast Iberian Continental Slope and Western Algero-Balearic Abyssal Plain

    NASA Astrophysics Data System (ADS)

    Lastras, G.; Canals, M.; León, C.; Elvira, E.; Pascual, L.; Muñoz, A.; de Cárdenas, E.; Acosta, J.

    2014-12-01

    We present the multibeam bathymetry and derived maps of the southeast Iberian margin from Cabo de Palos to Cabo de Gata, 37º35'N to 35º45'N and 2º10'W to 0º20'E, from the coastline down to the Algero-Balearic abyssal plain at depths exceeding 2,600 m. Data were obtained during different surveys in 2004, 2006 and 2007 on board R/V Vizconde de Eza with a Simrad EM300 multibeam echo-sounder, as part of the CAPESME Project, a collaboration between the Spanish Institute of Oceanography (IEO) and General Secretariat of Fisheries (SGP), aiming at creating maps of the fishing grounds of the Mediterranean continental margins of Spain. The edition of the maps has been carried out within the Complementary Action VALORPLAT (Scientific valorisation of multibeam bathymetry data from the Spanish continental shelf and slope), funded by the Spanish Ministry of Economy and Competitivity. Multibeam bathymetry data from the continental shelf obtained within the ESPACE project, also in a cooperative frame between IEO and SGP, completes the whole picture from the coastline to the deep abyssal plain. The map series is constituted by a general map at 1:400,000 scale and 14 detailed maps at 1:75,000 scale, which include inset maps on slope gradients and seafloor nature (rock or sediment type), the later obtained with rock dredges and Shipeck sediment dredges. Both the detailed maps and the general map are available in paper print, and the whole collection is also distributed in an edited USB. The geological features displayed in the different maps include the continental shelf, with abundant geomorphic features indicative of past sea-level changes, the continental slope carved by a large number of submarine canyons and gullies, including Palos, Tiñoso, Cartagena Este, Cartagena Oeste, Águilas, Almanzora, Alias, Garrucha and Gata submarine canyons, the Mazarrón, Palomares and Al-Mansour escarpments of probable tectonic origin, the Abubácer, Maimonides and Yusuf ridges, the

  4. Variations in the invertebrate abyssal megafauna in the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Thurston, M. H.; Bett, B. J.; Rice, A. L.; Jackson, P. A. B.

    1994-09-01

    Epibenthic sledge and otter trawl samples of invertebrate megabenthos were collected from the abyss of the northeastern Atlantic Ocean. Stations were selected to have contrasting overlying water column structure. Strong seasonal pulses of phytodetritus on the sea floor have been recorded on the Porcupine Abyssal Plain (PAP) but not on the Madeira Abyssal Plain (MAP). Sledge-and trawl-derived abundances of 13.73 and 8.13 individuals 10 3 m -2 were found at PAP, with corresponding wet biomass values of 169.4 and 189.2 g 10 3 m -2. Data from sledge hauls taken at MAP gave an abundance of 7.48 individuals and 5.15g 10 3 m -2. Sledge and trawl abundances at Great Meteor East (GME) were 2.91 and 2.19 individuals 10 3 m -2 and 4.31 and 11.30 g 10 3 m -2. Holothurians dominated the invertebrate biomass at PAP while Astoroidea and Decapoda Natantia were important taxa at MAP and GME. Otter trawl samples demonstrated fish to be the major component of total megadaunal biomass and suggest that small fixed-frame trawls give gross underestimates of fish abundance and biomass. Size spectra based on abundance and biomass data indicated the megafauna to be a functional group at PAP stationl only. Here peak invertebrate biomass occurred in the 40-80 g wet wt size class. In contrast, no large invertebrates (>20 g wet wt) were found at MAP of GME. Concurrent photographic records indicate higher faunal densities than do net catches. Faunal differences between stations were examined, and a weak relationship between surface productivity and megafaunal abundance was established. Data are inadequate to detect a similar relationship with biomass. Biomass values at PAP of 16-39 times those of MAP and GME appear to be explained by the deposition of phytodetritus at PAP but not at MAP or, probably, at GME. Among invertebrates, detritivores form the dominant feeding guild at all localities, but carnivores are important at MAP and GME. Phytodetritus appears to support the abundant surface

  5. Rich and rare—First insights into species diversity and abundance of Antarctic abyssal Gastropoda (Mollusca)

    NASA Astrophysics Data System (ADS)

    Schwabe, Enrico; Michael Bohn, Jens; Engl, Winfried; Linse, Katrin; Schrödl, Michael

    2007-08-01

    The abyssal depths of the polar oceans are thought to be low in diversity compared with the shallower polar shelves and temperate and tropical deep-sea basins. Our recent study on the gastropod fauna of the deep Southern Ocean gives evidence of the existence of a rich gastropod assemblage at abyssal depths. During the ANDEEP I and II expeditions to the southern Drake Passage, Northwestern Weddell Sea, and South Sandwich Trench, gastropods were collected by bottom and Agassiz trawls, epibenthic sledge, and multicorer, at 40 stations in depths between 127 and 5194 m. On the whole, 473 specimens, corresponding to 93 species of 36 families, were obtained. Of those, 414 specimens were caught below 750 m depth and refer to 84 (90%) benthic species of 32 (89%) families. Most families were represented by a single species only. The numerically dominant families were Skeneidae and Buccinidae (with 10 and 11 species, respectively), Eulimidae and Trochidae (with 9 species each), and Turridae (6 species). Thirty-Seven benthic deep-sea species (44%) were represented by a single specimen, and another 20 species (24%) were found at a single station, suggesting that more than two thirds of Antarctic deep-sea gastropod species are very rare or have a very scattered distribution. Of the 27 species occurring at two or more deep-sea stations, 14 were collected with different gear. Approximately half of the deep-water species are new to science or have been recently described. The present investigation increases the total number of recorded benthic Antarctic deep-sea gastropods (below 750 m) from 115 to 177. The previously known depth ranges have been extended, often considerably, for 31 species. The collected deep-sea gastropods comprise both eurybathic shelf species (29%) and apparently true deep-sea species (58%); some of the latter may belong to a so far unknown Antarctic abyssal fauna. Geographical ranges of the collected Antarctic benthic deep-sea gastropod species appear limited

  6. Loss estimates for a Puente Hills blind-thrust earthquake in Los Angeles, California

    USGS Publications Warehouse

    Field, E.H.; Seligson, H.A.; Gupta, N.; Gupta, V.; Jordan, T.H.; Campbell, K.W.

    2005-01-01

    Based on OpenSHA and HAZUS-MH, we present loss estimates for an earthquake rupture on the recently identified Puente Hills blind-thrust fault beneath Los Angeles. Given a range of possible magnitudes and ground motion models, and presuming a full fault rupture, we estimate the total economic loss to be between $82 and $252 billion. This range is not only considerably higher than a previous estimate of $69 billion, but also implies the event would be the costliest disaster in U.S. history. The analysis has also provided the following predictions: 3,000-18,000 fatalities, 142,000-735,000 displaced households, 42,000-211,000 in need of short-term public shelter, and 30,000-99,000 tons of debris generated. Finally, we show that the choice of ground motion model can be more influential than the earthquake magnitude, and that reducing this epistemic uncertainty (e.g., via model improvement and/or rejection) could reduce the uncertainty of the loss estimates by up to a factor of two. We note that a full Puente Hills fault rupture is a rare event (once every ???3,000 years), and that other seismic sources pose significant risk as well. ?? 2005, Earthquake Engineering Research Institute.

  7. Growth and interaction of active faults within a nascent shear zone, central Mojave Desert, California

    NASA Astrophysics Data System (ADS)

    Oskin, M.; Strane, M.

    2006-12-01

    Compilation of new slip-distribution and slip-rate data from the Mojave Desert portion of the Eastern California shear zone (ECSZ) lends insight into the role of fault growth and interaction of conjugate fault systems in accommodating shear. Dextral faults of the Mojave Desert ECSZ approach but do not appear to cut the bounding ENE-striking sinistral Pinto Mountain and Garlock faults. Differing styles of accommodation of these bounding faults occur at opposite ends of the 140 km-long NW-striking Hidalgo-Calico-Blackwater dextral fault system. Total slip and slip rate of the Blackwater fault gradually diminish northward. The fault terminates as a single strand with a zero-slip fault tip before intersecting the Garlock fault. In contrast, the Calico and Hidalgo faults spread displacement southward onto multiple fault strands spaced several kilometers apart. Active folding further distributes displacement onto the adjacent Bullion and Mesquite Lake faults. These mechanisms appear to maintain a uniform gradient of displacement approaching the Pinto Mountain fault. The highest displacement (9.8 ± 0.2 km) and slip rate (1.8 ± 0.3 mm/yr) occur in the central part of the Hidalgo-Calico-Blackwater fault system where strain is concentrated onto a single fault strand. A significant drop in total displacement and slip rate occurs along the northern Calico fault. Strain appears to be transferred here onto ENE-striking sinistral faults that separate domains of clockwise rotation in the central Mojave Desert. The kinematically incompatible intersection of sinistral and dextral faults is accommodated, at least in part, by active folding and uplift of the Calico Mountains and Mud Hills. Total slip and slip rate are not correlative for dextral faults of the Mojave ECSZ, indicating ongoing evolution of the fault network. For example, the Lenwood fault is a highly segmented, immature dextral fault with only 1.0 ± 0.1 km of total displacement yet its slip rate (1.5 ± 0.4 mm/yr) is

  8. SRTM Colored and Shaded Topography: Haro and Kas Hills, India

    NASA Technical Reports Server (NTRS)

    2001-01-01

    On January 26, 2001, the Kachchh region in western India suffered the most deadly earthquake in India's history. This shaded topography view of landforms northeast of the city of Bhuj depicts geologic structures that are of interest in the study the tectonic processes that may have led to that earthquake. However, preliminary field studies indicate that these structures are composed of Mesozoic rocks that are overlain by younger rocks showing little deformation. Thus these structures may be old, not actively growing, and not directly related to the recent earthquake.

    The Haro Hills are on the left and the Kas Hills are on the right. The Haro Hills are an 'anticline,' which is an upwardly convex elongated fold of layered rocks. In this view, the anticline is distinctly ringed by an erosion resistant layer of sandstone. The east-west orientation of the anticline may relate to the crustal compression that has occurred during India's northward movement toward, and collision with, Asia. In contrast, the largest of the Kas Hills appears to be a tilted (to the south) and faulted (on the north) block of layered rocks. Also seen here, the linear feature trending toward the southwest from the image center is an erosion-resistant 'dike,' which is an igneous intrusion into older 'host' rocks along a fault plane or other crack. These features are simple examples of how shaded topography can provide a direct input to geologic studies.

    In this image, colors show the elevation as measured by the Shuttle Radar Topography Mission (SRTM). Colors range from green at the lowest elevations, through yellow and red, to purple at the highest elevations. Elevations here range from near sea level to about 300 meters (about 1000 feet). Shading has been added, with illumination from the north (image top).

    Elevation data used in this image was acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same

  9. Deep ocean communities impacted by changing climate over 24 y in the abyssal northeast Pacific Ocean

    PubMed Central

    Smith, Kenneth L.; Ruhl, Henry A.; Kahru, Mati; Huffard, Christine L.; Sherman, Alana D.

    2013-01-01

    The deep ocean, covering a vast expanse of the globe, relies almost exclusively on a food supply originating from primary production in surface waters. With well-documented warming of oceanic surface waters and conflicting reports of increasing and decreasing primary production trends, questions persist about how such changes impact deep ocean communities. A 24-y time-series study of sinking particulate organic carbon (food) supply and its utilization by the benthic community was conducted in the abyssal northeast Pacific (∼4,000-m depth). Here we show that previous findings of food deficits are now punctuated by large episodic surpluses of particulate organic carbon reaching the sea floor, which meet utilization. Changing surface ocean conditions are translated to the deep ocean, where decadal peaks in supply, remineralization, and sequestration of organic carbon have broad implications for global carbon budget projections. PMID:24218565

  10. Kuril-Kamchatka deep sea revisited - insights into the amphipod abyssal fauna

    NASA Astrophysics Data System (ADS)

    Jażdżewska, Anna

    2015-01-01

    During the KuramBIO expedition to the Kuril-Kamchatka Trench and abyssal plain, benthic samples from the depths from 4987 to 5422 m were collected using a camera-epibenthic sledge. In this collection more than 1200 individuals of Amphipoda were found. They were assigned to 60 taxa (including 47 morphospecies) and 21 families. Until now 28 species being new to science have been found: six in the superfamily Eusiroidea and in the Oedicerotidae and Synopiidae families, four in the Phoxocephalidae, three in the Pardaliscidae, two in the Stenothoidae and one in the Pachynidae. The Synopiidae, Stenothoidae and Pachynidae were recorded for the first time in North-West Pacific area. The dominant and most speciose families were Oedicerotidae, Phoxocephalidae, Synopiidae, Eusiridae s.l. and Lysianassidae. The cluster analysis clearly separated the shallowest sample from the others, which were divided further into two groups. The shallowest sample was characterized by the highest number of species and number of individuals.

  11. Feeding Preferences of Abyssal Macrofauna Inferred from In Situ Pulse Chase Experiments

    PubMed Central

    Jeffreys, Rachel M.; Burke, Ciara; Jamieson, Alan J.; Narayanaswamy, Bhavani E.; Ruhl, Henry A.; Smith, Kenneth L.; Witte, Ursula

    2013-01-01

    Climatic fluctuations may significantly alter the taxonomic and biochemical composition of phytoplankton blooms and subsequently phytodetritus, the food source for the majority of deep-sea communities. To examine the response of abyssal benthic communities to different food resources we simulated a food sedimentation event containing diatoms and coccolithophorids at Station M in the NE Pacific. In one set of experiments we measured incorporation of diatomC and coccoN into the macrofauna using isotopically enriched 13C-diatoms and 15N-coccolithophores. In a second experiment we measured incorporation of C and N from dual-labelled (13C and 15N) diatoms. The second experiment was repeated 2 months later to assess the effect of seasonality. The simulated food pulses represented additions of 650 – 800 mg C m−2 and 120 mg N m−2 to the seafloor. In all cases rapid incorporation of tracer was observed within 4 days, with between 20% and 52% of the macrofauna displaying evidence of enrichment. However, incorporation levels of both diatomC and coccoN were low (<0.05% and 0.005% of the added C and N). Incorporation of labelled diatoms was similar during both June and September suggesting that the community was not food limited during either period. We found no evidence for selective ingestion of the different food types in the metazoan fauna suggesting that macrofauna do not have strong preferences for diatom vs. coccolithophore dominated phytodetrital pulses. C∶N ratios from both experiments suggest that the metazoan macrofauna community appear to have higher C demands and/or assimilation efficiencies compared to N. Concomitantly, the foraminifera preferentially selected for diatomN over coccoN, and we suggest that this may be related to foraminiferal requirements for intracellular nitrate. These experiments provide evidence that abyssal faunal feeding strategies are in part driven by an organism's internal stoichiometric budgets and biochemical requirements. PMID

  12. Source-To-Sink Perspectives On The Mississippi River System, Miocene To Present, Mountain To Abyss

    NASA Astrophysics Data System (ADS)

    Bentley, S. J.; Blum, M. D.

    2013-12-01

    . The objective of this study is to present a synthesis of the Mississippi River source-to-sink system, from montane source to abyssal sink, to elucidate specific geomorphic components and boundaries in the system, controls on mass transfer, and resultant geomorphic and statigraphic development. The Mississippi River source-to-sink system constitutes one of the largest sources, conduits, and depocenters of sediment on Earth, extending from elevations of 3.7 km in the Rocky Mountains to the Gulf of Mexico abyssal plain. Despite being one of the most intensely studied fluvial-marine systems in the world, comprehensive understanding and management of the system's resources remain a challenge. The system is valuable in many ways: it provides navigation and water to the heart of North America, and sustains extensive marine fisheries. The river has built a delta that is home to millions of people and yet is subsiding rapidly. Ancestral Mississippi fluvial-marine deposits continue to yield high-value petroleum resources to exploration. To address the range of temporal and spatial scales over which the system has developed and continues to evolve, we will focus on three geological time spans that display contrasting geologic forcing and response: Miocene, Pleistocene, and late Holocene. The present configuration of source, conduit, and sink were established during the Miocene epoch, when tectonics (via the uplifting southern Rockies, and later the rejuvenated Appalachians) and climate (wet in the east and dry in the west) provided abundant water and sediment to prograde the shelf margin and initiate deep-sea fan growth. Pleistocene continental glaciation, eustasy, and catastrophic drainage events further sculpted the alluvial valley, and extended the shelf margin, and fan. Studies of Modern processes and Holocene delta development have provided keys to both the delta's past and future evolution, in terms of cyclic autogenic lobe-switching, mass-transport events, storm

  13. Vesicomyinae (Bivalvia: Vesicomyidae) of the Kuril-Kamchatka Trench and adjacent abyssal regions

    NASA Astrophysics Data System (ADS)

    Krylova, Elena M.; Kamenev, Gennady M.; Vladychenskaya, Irina P.; Petrov, Nikolai B.

    2015-01-01

    Representatives of the subfamily Vesicomyinae (Bivalvia, Vesicomyidae) are tiny deep-sea molluscs distributed worldwide and reaching huge abundances of hundreds and thousands of specimens in trawl catches. During the German-Russian deep-sea expedition KuramBio (R/V Sonne, 2012) for the first time two vesicomyin species were collected from the abyssal plain adjacent to the Kuril-Kamchatka Trench from the depths of 4861-5787 m, Vesicomya pacifica (Smith, 1885) and "Vesicomya" filatovae sp.n. Two species of vesicomyins, V. sergeeviFilatova, 1971 and V. profundiFilatova, 1971, which were previously reported from the hadal of the Kuril-Kamchatka Trench, were not collected at the abyssal depth despite of the close geographical proximity of the sampling area to their distribution ranges. Altogether nine species of vesicomyins are recorded now from the West and Indo-West Pacific; data on distribution and morpho-anatomical characters of these species are provided. Taxonomic description of V. pacifica is revised including information on its soft part anatomy, new localities and COI sequences. For the first time for a vesicomyin bivalve molecular data is given for a species with an explicit morphological description and unambiguous taxonomic affiliation. Molecular analysis of 160 published COI sequences of vesicomyids and newly obtained molecular data on V. pacifica showed that V. pacifica and two undescribed vesicomyin species forming a monophyletic clade which exhibits sister relationships with the Pliocardiinae, the group of chemosymbiotic vesicomyids. "Vesicomya" filatovae sp.n. is provisionally assigned to the genus Vesicomya (s.l.) until additional morphological and molecular data are obtained. It differs from Vesicomya s.s. by a broader hinge margin with more radiating teeth and the presence of only one pair of demibranchs.

  14. Fault tree handbook

    SciTech Connect

    Haasl, D.F.; Roberts, N.H.; Vesely, W.E.; Goldberg, F.F.

    1981-01-01

    This handbook describes a methodology for reliability analysis of complex systems such as those which comprise the engineered safety features of nuclear power generating stations. After an initial overview of the available system analysis approaches, the handbook focuses on a description of the deductive method known as fault tree analysis. The following aspects of fault tree analysis are covered: basic concepts for fault tree analysis; basic elements of a fault tree; fault tree construction; probability, statistics, and Boolean algebra for the fault tree analyst; qualitative and quantitative fault tree evaluation techniques; and computer codes for fault tree evaluation. Also discussed are several example problems illustrating the basic concepts of fault tree construction and evaluation.

  15. Aseismic Slip Events along the Southern San Andreas Fault System Captured by Radar Interferometry

    SciTech Connect

    Vincent, P

    2001-10-01

    A seismic slip is observed along several faults in the Salton Sea and southernmost Landers rupture zone regions using interferometric synthetic aperture radar (InSAR) data spanning different time periods between 1992 and 1997. In the southernmost Landers rupture zone, projecting south from the Pinto Mountain Fault, sharp discontinuities in the interferometric phase are observed along the sub-parallel Burnt Mountain and Eureka Peak Faults beginning three months after the Landers earthquake and is interpreted to be post-Landers after-slip. Abrupt phase offsets are also seen along the two southernmost contiguous 11 km Durmid Hill and North Shore segments of the San Andreas Fault with an abrupt termination of slip near the northern end of the North Shore Segment. A sharp phase offset is seen across 20 km of the 30 km-long Superstition Hills Fault before phase decorrelation in the Imperial Valley along the southern 10 km of the fault prevents coherent imaging by InSAR. A time series of deformation interferograms suggest most of this slip occurred between 1993 and 1995 and none of it occurred between 1992 and 1993. A phase offset is also seen along a 5 km central segment of the Coyote Creek fault that forms a wedge with an adjoining northeast-southwest trending conjugate fault. Most of the slip observed on the southern San Andreas and Superstition Hills Faults occurred between 1993 and 1995--no slip is observed in the 92-93 interferograms. These slip events, especially the Burnt Mountain and Eureka Peak events, are inferred to be related to stress redistribution from the June, 1992 M{sub w} = 7.3 Landers earthquake. Best-fit elastic models of the San Andreas and Superstition Hills slip events suggest source mechanisms with seismic moments over three orders of magnitude larger than a maximum possible summation of seismic moments from all seismicity along each fault segment during the entire 4.8-year time interval spanned by the InSAR data. Aseismic moment releases of this

  16. Structure and evolution of the Horse Heaven Hills in South-Central Washington. [BWIP

    SciTech Connect

    Hagood, M.C.

    1986-03-01

    The purpose of this study is to describe the structure and evolution of the Horse Heaven Hills uplift at its abrupt structural transition. This was achieved by: (1) delineating the structure within the two trends as they approach the intersection; (2) determining the timing and location of uplift within each trend; (3) comparing and contrasting Miocene vertical growth rates along folds within both trends; and (4) imposing constraints for tectonic models that pertain to the genesis of the Horse Heaven Hills uplift. These objectives can only be fulfilled if the stratigraphy of the area is first delineated. Data from this study suggest that tectonic models that directly or indirectly pertain to the origin of the Horse Heaven Hills uplift may be constrained by: (1) the predominance of monoclinal or near-monoclinal fold geometries and reverse faults along both the northwest and northeast trends; (2) preliminary data which suggest clockwise rotation has occurred along folds of both trends; (3) folds along both trends developing simultaneously and at similar rates (at least during Wanapum and Saddle Mountains time); (4) folds along the northwest trend of the Horse Heaven Hills uplift being genetically related to and forming simultaneously with at least certain folds along the Rattlesnake-Wallula structural alignment; (5) the uplift developing simultaneously with the north-northwest-trending Hog Ranch-Naneum Ridge anticline as well as other Yakima folds during at least Columbia River Basalt Group time. It is proposed that folds of both trends of the Horse Heaven Hills uplift were generated by the same tectonic processes.

  17. Rupture process of the Ms 6.6 Superstition Hills, California, earthquake determined from strong-motion recordings: application of tomographic source inversion

    USGS Publications Warehouse

    Frankel, A.; Wennerberg, L.

    1989-01-01

    We analyze strong-motion recordings of the Ms6.6 Superstition Hills earthquake to determine the timing, location, spatial extent, and rupture velocity of the subevents that produced the bulk of the high-frequency (0.5 to 4Hz) seismic energy radiated by this shock. The earthquake can be characterized by three principal subevents, the largest ones occurring about 3 and 10sec after initiation of rupture. Timing relationships between pulses on the seismograms indicate that the three subevents are located within 8km of each other along the northern portion of the Superstition Hills fault. The two largest subevents display different directivity effects. We apply a tomographic source inversion to the integrated accelerograms to determine the slip acceleration on the fault as a function of time and distance, based on a one-dimensional fault model. -from Authors

  18. Development of Characterization Technology for Fault Zone Hydrology

    SciTech Connect

    Karasaki, Kenzi; Onishi, Tiemi; Gasperikova, Erika; Goto, Junichi; Tsuchi, Hiroyuki; Miwa, Tadashi; Ueta, Keiichi; Kiho, Kenzo; MIyakawa, Kimio

    2010-08-06

    Several deep trenches were cut, and a number of geophysical surveys were conducted across the Wildcat Fault in the hills east of Berkeley, California. The Wildcat Fault is believed to be a strike-slip fault and a member of the Hayward Fault System, with over 10 km of displacement. So far, three boreholes of ~;; 150m deep have been core-drilled and borehole geophysical logs were conducted. The rocks are extensively sheared and fractured; gouges were observed at several depths and a thick cataclasitic zone was also observed. While confirming some earlier, published conclusions from shallow observations about Wildcat, some unexpected findings were encountered. Preliminary analysis indicates that Wildcat near the field site consists of multiple faults. The hydraulic test data suggest the dual properties of the hydrologic structure of the fault zone. A fourth borehole is planned to penetrate the main fault believed to lie in-between the holes. The main philosophy behind our approach for the hydrologic characterization of such a complex fractured system is to let the system take its own average and monitor a long term behavior instead of collecting a multitude of data at small length and time scales, or at a discrete fracture scale and to ?up-scale,? which is extremely tenuous.

  19. Endolithic Microbial Communities in Fractures: Insights Gleaned from Mineralized Filaments in Cretaceous-age Calcite Veins in Serpentinized Peridotites, Iberia Abyssal Plain

    NASA Astrophysics Data System (ADS)

    Milliken, K. L.

    2001-03-01

    The occurrence of diverse mineralized microbial features in calcitized fractures in serpentinized peridotite, Iberia Abyssal Plain, suggests that mineralized fractures are of particular interest in the search for fossil or extant life on Mars.

  20. Matching, maximizing, and hill-climbing

    PubMed Central

    Hinson, John M.; Staddon, J. E. R.

    1983-01-01

    In simple situations, animals consistently choose the better of two alternatives. On concurrent variable-interval variable-interval and variable-interval variable-ratio schedules, they approximately match aggregate choice and reinforcement ratios. The matching law attempts to explain the latter result but does not address the former. Hill-climbing rules such as momentary maximizing can account for both. We show that momentary maximizing constrains molar choice to approximate matching; that molar choice covaries with pigeons' momentary-maximizing estimate; and that the “generalized matching law” follows from almost any hill-climbing rule. PMID:16812350

  1. Ruemker Hills - A lunar volcanic dome complex

    NASA Technical Reports Server (NTRS)

    Smith, E. I.

    1974-01-01

    The Ruemker Hills, a volcanic dome-flow complex in the northern Oceanus Procellarum, is characterized by overlapping plains-forming units with lobate scarps, volcanic domes, a 60-km ring, and a scarp which separates the plateau from surrounding mare materials. Plains-forming units are interpreted as fluid volcanic flows, and domes as viscous extrusions. One dome may be a stratovolcano. The ring system is discordant with regional structural trends and probably has a local origin. The Ruemker Hills is the closest lunar analog to the large Martian shield structures revealed on the Mariner 9 photographs of Mars.

  2. Hayward Fault rate constraints at Berkeley: Evaluation of the 335-meter Strawberry Creek offset

    NASA Astrophysics Data System (ADS)

    Williams, P. L.

    2007-12-01

    At UC Berkeley the active channel of Strawberry Creek is offset 335 meters by the Hayward fault and two abandoned channels of Strawberry Creek are laterally offset 580 and 730 meters. These relationships record the displacement of the northern Hayward fault at Berkeley over a period of tens of millennia. The Strawberry Creek site has a similar geometry to the central San Andreas fault's Wallace Creek site, which arguably provides the best geological evidence of "millennial" fault kinematics in California (Sieh and Jahns, 1984). Slip rate determinations are an essential component of overall hazard evaluation for the Hayward fault, and this site is ripe to disclose a long-term form of this parameter, to contrast with geodetic and other geological rate evidence. Large offsets at the site may lower uncertainty in the rate equation relative to younger sites, as the affect of stream abandonment age, generally the greatest source of rate uncertainty, is greatly reduced. This is helpful here because it more-than-offsets uncertainties resulting from piercing projections to the fault. Strawberry Creek and its ancestral channels suggest west-side-up vertical deformation across the Hayward fault at this location. The development of the vertical deformation parameter will complement ongoing geodetic measurements, particularly InSAR, and motivate testing of other geological constraints. Up-to-the-west motion across the Hayward fault at Berkeley has important implications for the partitioning of strain and kinematics of the northern Hayward fault, and may explain anomalous up-on-the-west landforms elsewhere along the fault. For example, geological features of the western Berkeley Hills are consistent with rapid and recent uplift to the west of the fault. On the basis of a preliminary analysis of the offset channels of Strawberry Creek, up-to-the-west uplift is about 0.5mm/yr across the Hayward fault at Berkeley. If this is in fact the long-term rate, the 150 m height of the Hills

  3. Fault zone hydrogeology

    NASA Astrophysics Data System (ADS)

    Bense, V. F.; Gleeson, T.; Loveless, S. E.; Bour, O.; Scibek, J.

    2013-12-01

    Deformation along faults in the shallow crust (< 1 km) introduces permeability heterogeneity and anisotropy, which has an important impact on processes such as regional groundwater flow, hydrocarbon migration, and hydrothermal fluid circulation. Fault zones have the capacity to be hydraulic conduits connecting shallow and deep geological environments, but simultaneously the fault cores of many faults often form effective barriers to flow. The direct evaluation of the impact of faults to fluid flow patterns remains a challenge and requires a multidisciplinary research effort of structural geologists and hydrogeologists. However, we find that these disciplines often use different methods with little interaction between them. In this review, we document the current multi-disciplinary understanding of fault zone hydrogeology. We discuss surface- and subsurface observations from diverse rock types from unlithified and lithified clastic sediments through to carbonate, crystalline, and volcanic rocks. For each rock type, we evaluate geological deformation mechanisms, hydrogeologic observations and conceptual models of fault zone hydrogeology. Outcrop observations indicate that fault zones commonly have a permeability structure suggesting they should act as complex conduit-barrier systems in which along-fault flow is encouraged and across-fault flow is impeded. Hydrogeological observations of fault zones reported in the literature show a broad qualitative agreement with outcrop-based conceptual models of fault zone hydrogeology. Nevertheless, the specific impact of a particular fault permeability structure on fault zone hydrogeology can only be assessed when the hydrogeological context of the fault zone is considered and not from outcrop observations alone. To gain a more integrated, comprehensive understanding of fault zone hydrogeology, we foresee numerous synergistic opportunities and challenges for the discipline of structural geology and hydrogeology to co-evolve and

  4. Anastomosing grabens, low-angle faults, and Tertiary thrust( ) faults, western Markagunt Plateau, southwestern Utah

    SciTech Connect

    Maldonado, F.; Sable, E.G. )

    1993-04-01

    A structurally complex terrane composed of grabens and horsts, low-angle faults, Tertiary thrust( ) faults, gravity-slide blocks, and debris deposits has been mapped along the western Markagunt Plateau, east of Parowan and Summit, southwestern Utah. This terrane, structurally situated within the transition between the Basin and Range and Colorado Plateau provinces, contains Tertiary volcanic and sedimentary and Cretaceous sedimentary rocks. The structures are mostly Miocene to Oligocene but some are Pleistocene. The oldest structure is the Red Hills low-angle shear zone, interpreted as a shallow structure that decoupled an upper plate composed of a Miocene-Oligocene volcanic ash-flow tuff and volcaniclastic succession from a lower plate of Tertiary sedimentary rocks. The period of deformation on the shear zone is bracketed from field relationships between 22.5 and 20 Ma. The graben-horst system trends northeast and formed after about 20 Ma (and probably much later) based on displacement of dated dikes and a laccolith. The central part of the system contains many grabens that merge toward its southerly end to become a single graben. Within these grabens, (1) older structures are preserved, (2) debris eroded from horst walls forms lobe-shaped deposits, (3) Pleistocene basaltic cinder cones have localized along graben-bounding faults, and (4) rock units are locally folded suggesting some component of lateral translation along graben-bounding faults. Megabreccia deposits and landslide debris are common. Megabreccia deposits are interpreted as gravity-slide blocks of Miocene-Oligocene( ) age resulting from formation of the Red Hills shear zone, although some may be related to volcanism, and still others to later deformation. The debris deposits are landslides of Pleistocene-Pliocene( ) age possibly caused by continued uplift of the Markagunt Plateau.

  5. OVERVIEW OF GOLD HILL MILL, ROAD, AND WARM SPRINGS CAMP ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    OVERVIEW OF GOLD HILL MILL, ROAD, AND WARM SPRINGS CAMP BUILDINGS, LOOKING SOUTH SOUTHEAST. THE FUNCTION OF THE FLAT AREA AT CENTER RIGHT IS UNKNOWN. - Gold Hill Mill, Warm Spring Canyon Road, Death Valley Junction, Inyo County, CA

  6. Hill-Burton Free and Reduced Cost Health Care

    MedlinePlus

    ... Hill-Burton Spanish Brochure (PDF - 83 KB) HHS Poverty Guidelines HHS Spanish Poverty Guidelines (PDF - 32 KB) Spanish Inquiry Letter (PDF - ... income is at or below the current HHS Poverty Guidelines . You may be eligible for Hill-Burton ...

  7. 3. GENERAL VIEW DOWN EAST HILLS DRIVE, BUILDING 20 (ONE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. GENERAL VIEW DOWN EAST HILLS DRIVE, BUILDING 20 (ONE BEDROOM) AND BUILDING 21 (TWO/THREE BEDROOM); ACTIVITY CENTER IN REAR, FACING NORTHEAST. - Aluminum City Terrace, East Hill Drive, New Kensington, Westmoreland County, PA

  8. 1. HISTORIC PHOTOGRAPH, VIEW OF ROUND HILL ROAD BRIDGE, LOOKING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. HISTORIC PHOTOGRAPH, VIEW OF ROUND HILL ROAD BRIDGE, LOOKING WEST, CA. 1940. CONNECTICUT DEPARTMENT OF TRANSPORTATION. - Merritt Parkway, Round Hill Road Bridge, Spanning Merritt Parkway at 3.5 mile mark, Greenwich, Fairfield County, CT

  9. EFFECTS OF THE 1906 EARTHQUAKE ON THE BALD HILL OUTLET SYSTEM, SAN MATEO COUNTY, CALIFORNIA.

    USGS Publications Warehouse

    Pampeyan, Earl H.

    1986-01-01

    Following the earthquake of April 18, 1906, it was discovered that a brick forebay and other parts of the reservoir outlet system were in the slip zone of the San Andreas fault. The original outlet through which water was directed to San Francisco consisted of two tunnels joined at the brick forebay; one tunnel extends 2,820 ft to the east under Bald Hill on Buri Buri Ridge, and the other tunnel intersects the lake bottom about 250 ft west of the forebay. In 1897 a second intake was added to the system, also joining the original forebay. During the present study the accessible parts of this original outlet system were examined with the hope of learning how the system had been affected by fault slip in 1906.

  10. Neogene Fault and Feeder Dike Patterns in the Western Ross Sea

    NASA Astrophysics Data System (ADS)

    Magee, W. R.; Wilson, T. J.

    2010-12-01

    In Antarctica, where much of the continent is covered by water and ice, geophysical data from the Antarctic submarine continental shelf is a fundamental part of reconstructing geological history. Multibeam sonar from the western Ross Sea has revealed elongate volcanic edifices and fields of elongate submarine hills on the seafloor. Origin of the submarine hills as carbonate mounds and drumlins have been proposed. The hills are up to ~8000m long and ~3500m wide, and rise 50-100m above the seafloor. Morphometric analysis of the hills shows they are elongate, with axial ratios ranging from 1.2:1 to 2:1, and some hills are linked to form elongate ridges. Seismic profiles show significant pull-ups directly below the hills, consistent with narrow, higher-density magmatic bodies; thus we favor an origin as volcanic seamounts above subsurface feeder dikes. If this volcanic hypothesis is correct, feeder dikes below the hills and elongate volcanic ridges may document magmatically-forced extension within the Terror Rift. The seamount field forms part of a regional en echelon array of volcanic ridges extending NNW from Beaufort Island toward Drygalski Ice Tongue. The ridges and elongate seamount cluster trend NNE, subparallel to mapped fault trends in this sector of the Terror Rift. This geometry is compatible with right-lateral transtension along this zone, as previously proposed for the Terror Rift as a whole. Volcanic islands and dredged volcanic ridges within the en echelon array are dated at ~7-4 Ma, implying Neogene deformation. We are completing a detailed analysis of orientation patterns and cross-cutting relations between faults and volcanic hills and their feeder systems to test this model for Neogene rift kinematics.

  11. Fault recovery characteristics of the fault tolerant multi-processor

    NASA Technical Reports Server (NTRS)

    Padilla, Peter A.

    1990-01-01

    The fault handling performance of the fault tolerant multiprocessor (FTMP) was investigated. Fault handling errors detected during fault injection experiments were characterized. In these fault injection experiments, the FTMP disabled a working unit instead of the faulted unit once every 500 faults, on the average. System design weaknesses allow active faults to exercise a part of the fault management software that handles byzantine or lying faults. It is pointed out that these weak areas in the FTMP's design increase the probability that, for any hardware fault, a good LRU (line replaceable unit) is mistakenly disabled by the fault management software. It is concluded that fault injection can help detect and analyze the behavior of a system in the ultra-reliable regime. Although fault injection testing cannot be exhaustive, it has been demonstrated that it provides a unique capability to unmask problems and to characterize the behavior of a fault-tolerant system.

  12. Reading Probe Will Continue on Capitol Hill

    ERIC Educational Resources Information Center

    Manzo, Kathleen Kennedy

    2007-01-01

    The recent wrap-up of an intensive, two-year examination of the federal Reading First initiative is not expected to halt debate over the program. Given the broad agreement in seven federal reports that serious problems occurred in the oversight of the program's implementation, the findings have sparked interest on Capitol Hill, as lawmakers…

  13. McGraw-Hill Authoring System.

    ERIC Educational Resources Information Center

    Bruce, A. Wayne

    1984-01-01

    Reviews the McGraw-Hill Interactive Authoring System which allows authors to create computer-based courses with or without interactive video. Use of the program requires no programming skills and authors do not need to learn a special language. The system's operation, performance, ease of use, documentation, and management are considered. (JN)

  14. ENHANCED REMEDIATION DEMONSTRATIONS AT HILL AFB: INTRODUCTION

    EPA Science Inventory

    Nine enhanced aquifer remediation technologies were demonstrated side-by-side at a Hill Air Force Base Chemical Disposal Pit/Fire Training Area site. The demonstrations were performed inside 3 x 5 m cells isolated from the surrounding shallow aquifer by steel piling. The site w...

  15. General Education at UNC-Chapel Hill

    ERIC Educational Resources Information Center

    Schalin, Jay; Robinson, Jenna Ashley

    2013-01-01

    The general education program at UNC-Chapel Hill has abandoned the concept of a core curriculum. Instead, students choose their "required" classes from lists of thousands of courses that may be as narrow and idiosyncratic as Love, Sex and Marriage in Soviet Culture (RUSS 277) or The Gardens, Shrines and Temples of Japan (ASIA 586).…

  16. 27 CFR 9.193 - Rattlesnake Hills.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Valley viticultural area (27 CFR 9.69). From the beginning point, the Rattlesnake Hills viticultural area boundary line— (2) Proceeds straight eastward, crossing onto the Elephant Mountain map, to the 2,192-foot...) Yakima East Quadrangle, Washington—Yakima Co., 1953, photorevised 1985; (2) Elephant Mountain...

  17. 27 CFR 9.193 - Rattlesnake Hills.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Valley viticultural area (27 CFR 9.69). From the beginning point, the Rattlesnake Hills viticultural area boundary line— (2) Proceeds straight eastward, crossing onto the Elephant Mountain map, to the 2,192-foot...) Yakima East Quadrangle, Washington—Yakima Co., 1953, photorevised 1985; (2) Elephant Mountain...

  18. The House on the Hill Challenge

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2011-01-01

    In this article, the author suggests a classroom challenge that will engage students in designing a house on the hill. He suggests teachers ask a local builder to come to the school to discuss the kinds of concerns that must be dealt with when building homes in cold environments. The use of dioramas and cardboard scale models would be very useful…

  19. Ocean Hill-Brownsville, 40 Years Later

    ERIC Educational Resources Information Center

    Kahlenberg, Richard D.

    2008-01-01

    Forty years ago--on May 9, 1968--the local school board in Brooklyn's black ghetto of Ocean Hill-Brownsville sent telegrams to 19 unionized educators, informing them that their employment in the district was terminated. Eighteen were white. One black teacher was mistakenly included on the list, but reinstated almost immediately after the error was…

  20. Tail prepivoting for the Hill estimator

    NASA Astrophysics Data System (ADS)

    Brito, Margarida; Moreira Freitas, Ana Cristina; Milhazes Freitas, Jorge

    2016-05-01

    It is well known that prepivoting reduces level error of confidence sets. We adapt this method to the context of the tail index estimation, introducing a procedure that we call tail prepivoting. We apply this procedure to the Hill estimator and establish its consistency.

  1. Jesse Stuart: Lessons from the Kentucky Hills.

    ERIC Educational Resources Information Center

    Sands, Lu

    1986-01-01

    Highlights events in the life of Jesse Stuart, who began his teaching career at the age of 17 in a remote one-room school in the Kentucky hills and went on to become widely recognized as teacher, lecturer, and significant regional writer. Emphasizes Stuart's love of teaching and his personal values. (JHZ)

  2. 27 CFR 9.121 - Warren Hills.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 1968 and 1973). (c) Boundary—(1) General. The Warren Hills viticultural area is located in Warren County, New Jersey. The beginning point of the following boundary description is the junction of the...). (2) Boundary Description. (i) From the beginning point, the boundary goes northeastward along...

  3. Chapel Hill, Berkeley Head Graduate Rankings.

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1983

    1983-01-01

    Provides lists ranking the 25 largest producers of bachelor's, certified bachelor's, master's, and doctoral graduates in chemistry. University of North Carolina (Chapel Hill) is the nation's largest producer of bachelor's degree chemistry graduates while the University of California (Berkeley) is the largest producer of Ph.D. chemistry graduates.…

  4. 27 CFR 9.197 - Clements Hills.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... viticultural area is located in San Joaquin County, California, and is entirely within the Lodi viticultural area (27 CFR 9.107). The Clements Hills viticultural areas boundary is as follows— (1) The beginning... 9.3 miles on Liberty Road to its junction with the San Joaquin-Amador County line, north of...

  5. 27 CFR 9.197 - Clements Hills.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... viticultural area is located in San Joaquin County, California, and is entirely within the Lodi viticultural area (27 CFR 9.107). The Clements Hills viticultural areas boundary is as follows— (1) The beginning... 9.3 miles on Liberty Road to its junction with the San Joaquin-Amador County line, north of...

  6. 27 CFR 9.197 - Clements Hills.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... viticultural area is located in San Joaquin County, California, and is entirely within the Lodi viticultural area (27 CFR 9.107). The Clements Hills viticultural areas boundary is as follows— (1) The beginning... 9.3 miles on Liberty Road to its junction with the San Joaquin-Amador County line, north of...

  7. 27 CFR 9.197 - Clements Hills.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... viticultural area is located in San Joaquin County, California, and is entirely within the Lodi viticultural area (27 CFR 9.107). The Clements Hills viticultural areas boundary is as follows— (1) The beginning... 9.3 miles on Liberty Road to its junction with the San Joaquin-Amador County line, north of...

  8. 27 CFR 9.197 - Clements Hills.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... viticultural area is located in San Joaquin County, California, and is entirely within the Lodi viticultural area (27 CFR 9.107). The Clements Hills viticultural areas boundary is as follows— (1) The beginning... 9.3 miles on Liberty Road to its junction with the San Joaquin-Amador County line, north of...

  9. An Unlikely Student Hits Capitol Hill

    ERIC Educational Resources Information Center

    Hoover, Eric

    2009-01-01

    Todd Sollar, a laid-off autoworker from Ohio who is studying for an associate degree in engineering at Sinclair Community College, in Dayton, OH, went to Capitol Hill to help educate lawmakers about the importance of including support for community colleges in the economic-stimulus bill. Mr. Sollar came to Washington with Sinclair's president, and…

  10. On A Simple Parameterization and Global Extrapolation of Topography-Catalyzed Diapycnal Mixing in the Abyssal Ocean

    NASA Astrophysics Data System (ADS)

    Decloedt, T.; Luther, D. S.

    2006-12-01

    The potential role of topography-catalyzed mixing in maintaining the observed abyssal stratification is re- examined in light of the growing body of fine- and micro-structure data revealing energetic mixing near rough topography. A large collection of these fine- and micro-structure data sets from various oceanic regions are employed to develop a simple parameterization of the mean vertical structure of diapycnal mixing. The parameterization depends only on seafloor roughness and a power law function of height above bottom. Resulting global diffusivity maps show considerable spatial variability and suggest the need for more exploration of regions where non-tidal energy sources may generate near-boundary mixing. Basin-average diffusivity profiles and total dissipation rate estimates are found to be sensitive to the strength of mixing very close to the boundary (within 200 m). The contention that topography-catalyzed mixing is an important factor in maintaining the abyssal stratification is supported. Near-boundary mixing is perhaps the dominant factor below 3 km of depth, and is a significant factor at depths as shallow as one kilometer where it may provide as much as 1/3 of the bulk diffusivity required to maintain the stratification (under the assumption that diapycnal mixing is the sole mechanism for maintaining the stratification). The power required by the model to sustain this basin-average diffusivity profile in the abyssal oceans (1-4 km depth, 40 S to 48 N) is 0.41 TW to 0.89 TW (depending on the maximum near-boundary diffusivity prescribed in the power law model), in contrast to about 0.65 TW to maintain a diffusivity of 1 Stoke in the abyssal oceans.

  11. Phytopigments as biomarkers of selectivity in abyssal holothurians; interspecific differences in response to a changing food supply

    NASA Astrophysics Data System (ADS)

    FitzGeorge-Balfour, Tania; Billett, David S. M.; Wolff, George A.; Thompson, Anu; Tyler, Paul A.

    2010-08-01

    Holothurians dominate the abyssal megabenthos. They are key consumers and bioturbators of surficial sediment. Compounds essential for holothurian reproduction, such as carotenoids, are in short supply in the deep ocean. Holothurians cannot synthesise carotenoids de novo; the compounds are supplied with the flux of phytodetritus. Therefore, the supply of these compounds may play an important role in regulating processes on the seafloor. This study examines the link between the diet of abyssal holothurians and their ovarian carotenoid biochemistry. Phytodetritus, surficial sediment, holothurian gut content and ovaries were sampled in June 2004 and in July 2005 at the Porcupine Abyssal Plain (PAP), NE Atlantic. Gut content chlorophyll a concentration showed that Amperima rosea, Peniagone diaphana and Oneirophanta mutabilis fed selectively on fresh organic matter, although when this was scarce, O. mutabilis was outcompeted and fed on more refractory material. All three species display consistent ovarian carotenoid profiles and have relatively high carotenoid concentrations in their ovaries. Psychropotes longicauda, Paroriza prouhoi, Pseudostichopus aemulatus, P. villosus and Molpadia blakei fed less selectively and exhibited low ovarian carotenoid concentrations with inconsistent profiles. The results suggest that abyssal holothurian ovarian biochemistry is a complex function of OM supply, holothurian feeding guild and reproductive adaptation. Changes in upper ocean biogeochemistry, altering the composition of organic matter reaching the deep-sea floor, may favour certain holothurian species, as suggested by the interspecific differences in holothurian ovarian biochemistry. This may lead to large community changes as seen at the PAP, which can alter the reworking rates of sediment, probably affecting carbon burial. The study also demonstrated that using the presence of biomarkers in gut contents to infer feeding selectivity should be used with caution. Only biomarkers

  12. Changes in rate of fault creep

    USGS Publications Warehouse

    Harsh, P.

    1979-01-01

    Aseismic slip or fault creep is occurring on many faults in California. Although the creep rates are generally less than 10 mm/yr in most regions, the maximum observed rate along the San Andreas fault between San Juan Bautista and Gold Hill in central California exceeds 30 mm/yr. Changes in slip rates along a 162 km segment of the San Andreas fault in this region have occurred at approximately the same time at up to nine alinement array sites. Rates of creep on the fault near the epicenters of moderate earthquakes (ML 4-6) vary for periods of several years, decreasing before the main shocks and increasing thereafter, in agreement with prior observations based on creepmeter results. The change of surface slip rate is most pronounced within the epicentral region defined by aftershocks, but records from sites at distances up to 100 km show similar variations. Additionally, some variations in rate, also apparently consistent among many sites, have a less obvious relation with seismic activity and have usually taken place over shorter periods. Not all sites exhibit a significant variation in rate at the time of a regional change, and the amplitudes of the change at nearby sites are not consistently related. The time intervals between measurements at the nine array sites during a given period have not always been short with respect to the intervals between surveys at one site; hence, uneven sampling intervals may bias the results slightly. Anomalies in creep rates thus far observed, therefore, have not been demonstrably consistent precursors to moderate earthquakes; and in the cases when an earthquake has followed a long period change of rate, the anomaly has not specified time, place, or magnitude with a high degree of certainty. The consistency of rate changes may represent a large scale phenomenon that occurs along much of the San Andreas transform plate boundary. ?? 1979.

  13. 78 FR 65962 - Black Hills National Forest Advisory Board

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-04

    ... Forest Service Black Hills National Forest Advisory Board AGENCY: Forest Service, USDA. ACTION: Notice of cancellation of meeting of the Black Hills National Forest Advisory Board. SUMMARY: The U. S. Department of Agriculture, Forest Service, Black Hills National Forest cancelled the October 16, 2013 meeting of the...

  14. 77 FR 22755 - Black Hills National Forest Advisory Board

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-17

    ...; ] DEPARTMENT OF AGRICULTURE Forest Service Black Hills National Forest Advisory Board AGENCY: USDA Forest Service. ACTION: Notice of cancellation of meetings of the Black Hills National Forest Advisory Board. SUMMARY: The U. S. Department of Agriculture, Forest Service, Black Hills National Forest was required...

  15. View of south boundary of Easter Hill project site, former ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of south boundary of Easter Hill project site, former right of way for Hoffman Boulevard. Note reconstructed Easter Hill Building No. 6 at rear. Looking east - Easter Hill Village, Bordered by South Twenty-sixth Street, South Twenty-eighth Street, Hinkley Avenue, Foothill Avenue & Corto Square, Richmond, Contra Costa County, CA

  16. 27 CFR 9.169 - Red Hills Lake County.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Red Hills Lake County. 9... Red Hills Lake County. (a) Name. The name of the viticultural area described in this section is “Red Hills Lake County”. (b) Approved Map. The appropriate maps for determining the boundary of the Red...

  17. 27 CFR 9.169 - Red Hills Lake County.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Red Hills Lake County. 9... Red Hills Lake County. (a) Name. The name of the viticultural area described in this section is “Red Hills Lake County”. (b) Approved Map. The appropriate maps for determining the boundary of the Red...

  18. 27 CFR 9.169 - Red Hills Lake County.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Red Hills Lake County. 9... Red Hills Lake County. (a) Name. The name of the viticultural area described in this section is “Red Hills Lake County”. (b) Approved Map. The appropriate maps for determining the boundary of the Red...

  19. 27 CFR 9.169 - Red Hills Lake County.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Red Hills Lake County. 9... Red Hills Lake County. (a) Name. The name of the viticultural area described in this section is “Red Hills Lake County”. (b) Approved Map. The appropriate maps for determining the boundary of the Red...

  20. 27 CFR 9.169 - Red Hills Lake County.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Red Hills Lake County. 9... Red Hills Lake County. (a) Name. The name of the viticultural area described in this section is “Red Hills Lake County”. (b) Approved Map. The appropriate maps for determining the boundary of the Red...

  1. 3. HYDE STREET HILL: View to north looking down the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. HYDE STREET HILL: View to north looking down the Hyde Street hill from Lombard Street. The steepest hill on the present cable railway system, this grade exceeds 20%. - San Francisco Cable Railway, Washington & Mason Streets, San Francisco, San Francisco County, CA

  2. 27 CFR 9.136 - Texas Hill Country.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Texas Hill Country. 9.136... Texas Hill Country. (a) Name. The name of the viticultural area described in this section is “Texas Hill Country.” (b) Approved maps. The appropriate maps for determining the boundaries of the “Texas...

  3. 27 CFR 9.136 - Texas Hill Country.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Texas Hill Country. 9.136... Texas Hill Country. (a) Name. The name of the viticultural area described in this section is “Texas Hill Country.” (b) Approved maps. The appropriate maps for determining the boundaries of the “Texas...

  4. 27 CFR 9.136 - Texas Hill Country.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Texas Hill Country. 9.136... Texas Hill Country. (a) Name. The name of the viticultural area described in this section is “Texas Hill Country.” (b) Approved maps. The appropriate maps for determining the boundaries of the “Texas...

  5. 27 CFR 9.136 - Texas Hill Country.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Texas Hill Country. 9.136... Texas Hill Country. (a) Name. The name of the viticultural area described in this section is “Texas Hill Country.” (b) Approved maps. The appropriate maps for determining the boundaries of the “Texas...

  6. 27 CFR 9.136 - Texas Hill Country.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Texas Hill Country. 9.136... Texas Hill Country. (a) Name. The name of the viticultural area described in this section is “Texas Hill Country.” (b) Approved maps. The appropriate maps for determining the boundaries of the “Texas...

  7. Dynamics of Melting and Melt Migration as Inferred from Incompatible Trace Element Abundance in Abyssal Peridotites

    NASA Astrophysics Data System (ADS)

    Peng, Q.; Liang, Y.

    2008-12-01

    To better understand the melting processes beneath the mid-ocean ridge, we developed a simple model for trace element fractionation during concurrent melting and melt migration in an upwelling steady-state mantle column. Based on petrologic considerations, we divided the upwelling mantle into two regions: a double- lithology upper region where high permeability dunite channels are embedded in a lherzolite/harzburgite matrix, and a single-lithology lower region that consists of partially molten lherzolite. Melt generated in the single lithology region migrates upward through grain-scale diffuse porous flow, whereas melt in the lherzolite/harzburgite matrix in the double-lithology region is allowed to flow both vertically through the overlying matrix and horizontally into its neighboring dunite channels. There are three key dynamic parameters in our model: degree of melting experienced by the single lithology column (Fd), degree of melting experienced by the double lithology column (F), and a dimensionless melt suction rate (R) that measures the accumulated rate of melt extraction from the matrix to the channel relative to the accumulated rate of matrix melting. In terms of trace element fractionation, upwelling and melting in the single lithology column is equivalent to non-modal batch melting (R = 0), whereas melting and melt migration in the double lithology region is equivalent to a nonlinear combination of non-modal batch and fractional melting (0 < R < 1). Given the nonlinear nature of the melting model and uncertainties in trace element data for the abyssal peridotite, we showed, with the help of Monte Carlo simulations, that it is difficult to invert for all three dynamic parameters from a set of incompatible trace element data with confidence. However, given Fd, it is quite possible to constrain F and R from incompatible trace element abundances in residual peridotite. As an illustrative example, we used the simple melting model developed in this study and

  8. The regional structural setting of the 2008 Wells earthquake and Town Creek Flat Basin: implications for the Wells earthquake fault and adjacent structures

    USGS Publications Warehouse

    Henry, Christopher S.; Colgan, Joseph P.

    2011-01-01

    The 2008 Wells earthquake occurred on a northeast-striking, southeast-dipping fault that is clearly delineated by the aftershock swarm to a depth of 10-12 km below sea level. However, Cenozoic rocks and structures around Wells primarily record east-west extension along north- to north-northeast-striking, west-dipping normal faults that formed during the middle Miocene. These faults are responsible for the strong eastward tilt of most basins and ranges in the area, including the Town Creek Flat basin (the location of the earthquake) and the adjacent Snake Mountains and western Windermere Hills. These older west-dipping faults are locally overprinted by a younger generation of east-dipping, high-angle normal faults that formed as early as the late Miocene and have remained active into the Quaternary. The most prominent of these east-dipping faults is the set of en-échelon, north-striking faults that bounds the east sides of the Ruby Mountains, East Humboldt Range, and Clover Hill (about 5 km southwest of Wells). The northeastern-most of these faults, the Clover Hill fault, projects northward along strike toward the Snake Mountains and the approximately located surface projection of the Wells earthquake fault as defined by aftershock locations. The Clover Hill fault also projects toward a previously unrecognized, east-facing Quaternary fault scarp and line of springs that appear to mark a significant east-dipping normal fault along the western edge of Town Creek Flat. Both western and eastern projections may be northern continuations of the Clover Hill fault. The Wells earthquake occurred along this east-dipping fault system. Two possible alternatives to rupture of a northern continuation of the Clover Hill fault are that the earthquake fault (1) is antithetic to an active west-dipping fault or (2) reactivated a Mesozoic thrust fault that dips east as a result of tilting by the west-dipping faults along the west side of the Snake Mountains. Both alternatives are

  9. Subsurface structure along the eastern marginal fault zone of Yokote Basin by Seismic reflection profiling studies, Northeast Japan

    NASA Astrophysics Data System (ADS)

    Kagohara, K.; Imaizumi, T.; Echigo, T.; Miyauchi, T.; Sato, H.

    2005-12-01

    Typical reverse faults, which are known as Senya earthquake faults appeared along the western foot of the Mahiru Mountains, associated with The Rikuu Earthquake (Mj7.2) of 1896 in Northeast Japan. Eastern marginal fault zone of the Yokote Basin consist of four main surface ruptures, about 35 km long, Obonai fault, Shiraiwa fault, Ota fault and Senya fault, depending on their continuity and strike (Matsuda et al., 1980). We carried out the seismic reflection profiling across these faults (Kawaguchi03 Seismic line, Unjono04 Seismic line and Kotaki05 Seismic line) to clarify the subsurface structure of these reverse fault system based on the data of tectonic geomorphology and structural geology and furthermore, to discuss the timing of migration of the thrusting from the range front to the basin margin. The seismic source was mini-vibrator trucks, with 20seconds of 10-100Hz signals at 10m or 5m intervals. The sweep signals were recorded by a digital telemetry system (GDAPS-4a) with 10 Hz geophones. The obtained seismic reflection data were processed by conventional Common mid-point (CMP) methods, including post-stack migration and depth conversion. The resulting seismic reflection profile reveals a thrust structure beneath these areas. At the Center of Senya hills there are two thrusts and one high angle reverse fault (1997 Seismic Line). Senya fault is an active frontal emergent thrust with flat and ramp structure. Although, the high angle reverse fault, located along the foot of the range is a short-cut branching fault from the Senya fault in the central part of the Senya hill (Sato et al., 1998), in the Unjono04 seismic line, the depth of the flat and ramp structure gradually shallow in the north part of the Senya hill, where the flexure scarp accompanied with antithetic faults formed on the fluvial terraces. In the Kawaguchi03 seismic line, the concealed fault, 0.5km below the surface, branched from the master Ota fault, form a flexure scarplet on the alluvial fan

  10. Abyssal fauna of the UK-1 polymetallic nodule exploration claim, Clarion-Clipperton Zone, central Pacific Ocean: Echinodermata.

    PubMed

    Glover, Adrian G; Wiklund, Helena; Rabone, Muriel; Amon, Diva J; Smith, Craig R; O'Hara, Tim; Mah, Christopher L; Dahlgren, Thomas G

    2016-01-01

    We present data from a DNA taxonomy register of the abyssal benthic Echinodermata collected as part of the Abyssal Baseline (ABYSSLINE) environmental survey cruise 'AB01' to the UK Seabed Resources Ltd (UKSRL) polymetallic-nodule exploration claim 'UK-1' in the eastern Clarion-Clipperton Zone (CCZ), central Pacific Ocean abyssal plain. Morphological and genetic data are presented for 17 species (4 Asteroidea, 4 Crinoidea, 2 Holothuroidea and 7 Ophiuroidea) identified by a combination of morphological and genetic data. No taxa matched previously published genetic sequences, but 8 taxa could be assigned to previously-described species based on morphology, although here we have used a precautionary approach in taxon assignments to avoid over-estimating species ranges. The Clarion-Clipperton Zone is a region undergoing intense exploration for potential deep-sea mineral extraction. We present these data to facilitate future taxonomic and environmental impact study by making both data and voucher materials available through curated and accessible biological collections. PMID:26929713

  11. Abyssal fauna of the UK-1 polymetallic nodule exploration claim, Clarion-Clipperton Zone, central Pacific Ocean: Echinodermata

    PubMed Central

    Glover, Adrian G; Wiklund, Helena; Rabone, Muriel; Amon, Diva J; Smith, Craig R; O'Hara, Tim; Mah, Christopher L

    2016-01-01

    Abstract We present data from a DNA taxonomy register of the abyssal benthic Echinodermata collected as part of the Abyssal Baseline (ABYSSLINE) environmental survey cruise ‘AB01’ to the UK Seabed Resources Ltd (UKSRL) polymetallic-nodule exploration claim ‘UK-1’ in the eastern Clarion-Clipperton Zone (CCZ), central Pacific Ocean abyssal plain. Morphological and genetic data are presented for 17 species (4 Asteroidea, 4 Crinoidea, 2 Holothuroidea and 7 Ophiuroidea) identified by a combination of morphological and genetic data. No taxa matched previously published genetic sequences, but 8 taxa could be assigned to previously-described species based on morphology, although here we have used a precautionary approach in taxon assignments to avoid over-estimating species ranges. The Clarion-Clipperton Zone is a region undergoing intense exploration for potential deep-sea mineral extraction. We present these data to facilitate future taxonomic and environmental impact study by making both data and voucher materials available through curated and accessible biological collections. PMID:26929713

  12. Abyssal intimacies and temporalities of care: How (not) to care about deformed leaf bugs in the aftermath of Chernobyl.

    PubMed

    Schrader, Astrid

    2015-10-01

    Prompted by a classroom discussion on knowledge politics in the aftermath of the Chernobyl disaster, this article offers a reading of Hugh Raffles' Insectopedia entry on Chernobyl. In that entry, Raffles describes how Swiss science-artist and environmental activist Cornelia Hesse-Honegger collects, studies, and paints morphologically deformed leaf bugs that she finds in the proximity of nuclear power plants. In exploring how to begin to care about beings, such as leaf bugs, this article proposes a notion of care that combines an intimate knowledge practice with an ethical relationship to more-than-human others. Jacques Derrida's notion of 'abyssal intimacy' is central to such a combination. Hesse-Honegger's research practices enact and her paintings depict an 'abyssal intimacy' that deconstructs the oppositions between concerns about human suffering and compassion for seemingly irrelevant insects and between knowledge politics and ethics. At the heart of such a careful knowledge production is a fundamental passivity, based on a shared vulnerability. An abyssal intimacy is not something we ought to recognize; rather, it issues from particular practices of care that do not identify their subjects of care in advance. Caring or becoming affected thus entails the dissociation of affection not only from the humanist subject, but also from movements in time: from direct helping action and from the assumption that advocacy necessarily means speaking for an other, usually assumed to be inferior. PMID:26630816

  13. Reconnaissance Seismic Refraction Studies at Calico Hills, Wahmonie, and Yucca Mountain, Southwest Nevada Test Site, Nye County, Nevada

    USGS Publications Warehouse

    Pankratz, L.W.

    1982-01-01

    Reconnaissance refraction surveys consisting off a total of 5 spreads were conducted in the Calico Hills, Wahmonie and Yucca Mountain areas, southwestern Nevada Test Site (NTS). Data from Calico Hills and Wahmonie are generally high in quality; data from Yucca Mountain are for the most part low in quality. At Calico Hills and Wahmonie, special attention was focused on the possible occurrence of a major intrusive body at depth. At Calico Hills this occurrence is supported by an inferred dome-shaped velocity interface. possibly associated with the roof of an altered phase of argillite. However, if an intrusive body is present, its top must be buried deeper than 3 km or it must be so pervasively altered that its velocity is similar to that of the calcareous argillite encountered at the bottom of drill hole DE 25a-3. At Wahmonie, the seismic data suggest the occurrence of a massive lenticular unit within 60 m of the ground surface, probably consisting of argillite but possibly consisting of intensively altered intrusive rock. At Yucca Mountain, preliminary interpretations of the most reliable data suggest the occurrence of a major, steeply inclined velocity interface 500 m from the southwest end of the Yucca C spread. This interface may represent a major fault or erosional feature separating the Topopah Spring and Tiva Canyon Members with Paintbrush Tuff at depth. This interface is 800 m east of a previously mapped fault. On the basis of poor-quality data obtained at Yucca Mountain, the subsurface velocity distribution appears to be complex. For example, one spread near drill hole UE25 a-I suggests not only a much thicker section of Tiva but also that this material is down thrown in the valley. This may suggest faulting with throws exceeding 100 meters or an equivalent erosional feature.

  14. Structure, stratigraphy, and origin of Husband Hill, Columbia Hills, Gusev Crater, Mars

    USGS Publications Warehouse

    McCoy, T.J.; Sims, M.; Schmidt, M.E.; Edwards, L.; Tornabene, L.L.; Crumpler, L.S.; Cohen, B. A.; Soderblom, L.A.; Blaney, D.L.; Squyres, S. W.; Arvidson, R. E.; Rica, J.W.; Treguier, E.; d'Uston, C.; Grant, J. A.; McSween, H.Y.; Golombek, M.P.; Haldemann, A.F.C.; de Souza, P.A.

    2008-01-01

    The strike and dip of lithologic units imaged in stereo by the Spirit rover in the Columbia Hills using three-dimensional imaging software shows that measured dips (15-32??) for bedding on the main edifice of the Columbia Hill are steeper than local topography (???8-10??). Outcrops measured on West Spur are conformable in strike with shallower dips (7-15??) than observed on Husband Hill. Dips are consistent with observed strata draping the Columbia Hills. Initial uplift was likely related either to the formation of the Gusev Crater central peak or ring or through mutual interference of overlapping crater rims. Uplift was followed by subsequent draping by a series of impact and volcaniclastic materials that experienced temporally and spatially variable aqueous infiltration, cementation, and alteration episodically during or after deposition. West Spur likely represents a spatially isolated depositional event. Erosion by a variety of processes, including mass wasting, removed tens of meters of materials and formed the Tennessee Valley primarily after deposition. This was followed by eruption of the Adirondack-class plains basalt lava flows which embayed the Columbia Hills. Minor erosion, impact, and aeolian processes have subsequently modified the Columbia Hills. Copyright 2008 by the American Geophysical Union.

  15. Abyssal θ-S Observations at Hawaii Ocean Time-series Station ALOHA

    NASA Astrophysics Data System (ADS)

    Lukas, R.; Santiago-Mandujano, F.; Fumar, C.; McCoy, D.; Deppe, R. W.; Gum, J.; Snyder, J.; Chee, B.; Howe, B. M.; Potemra, J. T.; Duennebier, F. K.

    2014-12-01

    Abyssal θ-S variations observed since June 2011 by the ALOHA Cabled Observatory (ACO) reveal a potential temperature range of 0.025°C, and a salinity range of more than 0.0025 g kg-1. The very large temperature range is associated with episodic cold events (Lukas et al.2001; Alford et al. 2011). The salinity range, while not large in absolute terms, is an order of magnitude larger than the precision of the Sea-Bird Microcat. The absolute salinity is calibrated against simultaneous Hawaii Ocean Time-series (HOT) full-depth CTD profiles that have an accuracy of ~10-3 g kg-1. A slow drift of the SBE-37 conductivity sensor is seen, along with a sudden offset that may have been caused by a nearby glass ball implosion. θ-S variations are dominated by changes in density that are associated with dynamic processes. Large cooling events are associated with increases of salinity ultimately deriving from the neighboring Maui Deep. The slopes of these excursions in θ-S space are consistent with the slopes of HOT CTD depth profiles, suggesting that these are vertical changes due either to gravity currents associated with cold, salty overflow events from the Maui Deep, or to internal seiches within the Kauai Deep. θ-S variations that are nearly isopycnal are also seen during the slow recovery from a major cooling event in 2011. This may be due to diapycnal mixing with fresher waters above the controlling sill depth. It cannot be ruled out that some apparent salinity changes may be associated with sediment resuspension events, with subsequent deviations from the PSS-78 empirical relationship between conductivity, salinity, temperature and pressure. ADCP records show large vacillations of along- and cross-isobath flow. Large vertical current variations are measured that are correlated with horizontal flows, likely due to the bottom slope, even after minimizing correlations to account for the unknown orientation of the ADCP. The primary conclusion is that abyssal dynamics

  16. Suspended particulate loads and transports in the nepheloid layer of the abyssal Atlantic Ocean

    USGS Publications Warehouse

    Biscaye, P.E.; Eittreim, S.L.

    1977-01-01

    Vertical profiles of light scattering from over 1000 L-DGO nephelometer stations in the Atlantic Ocean have been used to calculate mass concentrations of suspended particles based on a calibration from the western North American Basin. From these data are plotted the distributions of particulate concentrations at clear water and in the more turbid near-bottom water. Clear water is the broad minimum in concentration and light scattering that occurs at varying mid-depths in the water column. Concentrations at clear water are as much as one-to-two orders of magnitude lower than those in surface water but still reflect a similar geographic distribution: relatively higher concentrations at ocean margins, especially underneath upwelling areas, and the lowest concentrations underneath central gyre areas. These distributions within the clear water reflect surface-water biogenic productivity, lateral injection of particles from shelf areas and surface circulation patterns and require that the combination of downward vertical and horizontal transport processes of particles retain this pattern throughout the upper water column. Below clear water, the distribution of standing crops of suspended particulate concentrations in the lower water column are presented. The integration of mass of all particles per unit area (gross particulate standing crop) reflects a relative distribution similar to that at the surface and at clear water levels, superimposed on which is the strong imprint of boundary currents along the western margins of the Atlantic. Reducing the gross particulate standing crop by the integral of the concentration of clear water yields a net particulate standing crop. The distribution of this reflects primarily the interaction of circulating abyssal waters with the ocean bottom, i.e. a strong nepheloid layer which is coincident with western boundary currents and which diminishes in intensity equatorward. The resuspended particulate loads in the nepheloid layer of the

  17. Fault model development for fault tolerant VLSI design

    NASA Astrophysics Data System (ADS)

    Hartmann, C. R.; Lala, P. K.; Ali, A. M.; Visweswaran, G. S.; Ganguly, S.

    1988-05-01

    Fault models provide systematic and precise representations of physical defects in microcircuits in a form suitable for simulation and test generation. The current difficulty in testing VLSI circuits can be attributed to the tremendous increase in design complexity and the inappropriateness of traditional stuck-at fault models. This report develops fault models for three different types of common defects that are not accurately represented by the stuck-at fault model. The faults examined in this report are: bridging faults, transistor stuck-open faults, and transient faults caused by alpha particle radiation. A generalized fault model could not be developed for the three fault types. However, microcircuit behavior and fault detection strategies are described for the bridging, transistor stuck-open, and transient (alpha particle strike) faults. The results of this study can be applied to the simulation and analysis of faults in fault tolerant VLSI circuits.

  18. FTAPE: A fault injection tool to measure fault tolerance

    NASA Technical Reports Server (NTRS)

    Tsai, Timothy K.; Iyer, Ravishankar K.

    1995-01-01

    The paper introduces FTAPE (Fault Tolerance And Performance Evaluator), a tool that can be used to compare fault-tolerant computers. The tool combines system-wide fault injection with a controllable workload. A workload generator is used to create high stress conditions for the machine. Faults are injected based on this workload activity in order to ensure a high level of fault propagation. The errors/fault ratio and performance degradation are presented as measures of fault tolerance.

  19. FTAPE: A fault injection tool to measure fault tolerance

    NASA Technical Reports Server (NTRS)

    Tsai, Timothy K.; Iyer, Ravishankar K.

    1994-01-01

    The paper introduces FTAPE (Fault Tolerance And Performance Evaluator), a tool that can be used to compare fault-tolerant computers. The tool combines system-wide fault injection with a controllable workload. A workload generator is used to create high stress conditions for the machine. Faults are injected based on this workload activity in order to ensure a high level of fault propagation. The errors/fault ratio and performance degradation are presented as measures of fault tolerance.

  20. FTAPE: A fault injection tool to measure fault tolerance

    NASA Astrophysics Data System (ADS)

    Tsai, Timothy K.; Iyer, Ravishankar K.

    1994-07-01

    The paper introduces FTAPE (Fault Tolerance And Performance Evaluator), a tool that can be used to compare fault-tolerant computers. The tool combines system-wide fault injection with a controllable workload. A workload generator is used to create high stress conditions for the machine. Faults are injected based on this workload activity in order to ensure a high level of fault propagation. The errors/fault ratio and performance degradation are presented as measures of fault tolerance.

  1. The Gas Hills uranium district and some probable controls for ore deposition

    USGS Publications Warehouse

    Zeller, Howard Davis

    1957-01-01

    Uranium deposits occur in the upper coarse-grained facies of the Wind River formation of Eocene age in the Gas Hills district of the southern part of the Wind River Basin. Some of the principal deposits lie below the water table in the unoxidized zone and consist of uraninite and coffinite occurring as interstitial fillings in irregular blanket-like bodies. In the near-surface deposits that lie above the water table, the common yellow uranium minerals consist of uranium phosphates, silicates, and hydrous oxides. The black unoxidized uraninite -coffinite ores show enrichment of molybdenum, arsenic, and selenium when compared to the barren sandstone. Probable geologic controls for ore deposits include: 1) permeable sediments that allowed passage of ore-bearing solutions; 2) numerous faults that acted as impermeable barriers impounding the ore -bearing solutions; 3) locally abundant pyrite, carbonaceous material, and natuial gas containing hydrogen sulfide that might provide a favorable environment for precipitation of uranium. Field and laboratory evidence indicate that the uranium deposits in the Gas Hills district are very young and related to the post-Miocene to Pleistocene regional tilting to the south associated with the collapse of the Granite Mountains fault block. This may have stopped or reversed ground water movement from a northward (basinward) direction and alkaline ground water rich in carbonate could have carried the uranium into the favorable environment that induced precipitation.

  2. Evidence in Support of Sulfide Partial Melting at Broken Hill Australia and Broken Hill, South Africa

    NASA Astrophysics Data System (ADS)

    Sparks, H. A.; Mavrogenes, J. A.

    2004-05-01

    In the past there has been much debate over the genesis of Broken Hill, Australia and Broken Hill, South Africa since many of the original characteristics have been obscured by high-grade metamorphism and intense deformation. The idea that a sulfide melt can form from partial melting of pre-existing ore during metamorphism was first proposed by Brett and Kullerud (1967 Economic Geology) and Lawrence (1967 Mineral Deposita), but was largely ignored due to a lack of direct field and experimental evidence. However, recent experimental support in the system PbS-Fe0.96S-ZnS-(1% Ag2S) determined a quaternary eutectic melt at 795 700° C at 5 kbar (Mavrogenes et al., 2001 Economic Geology), clear indirect evidence that at least some of the Broken Hill lodes partially melted during metamorphism. Features at both Broken Hill, Australia and Broken Hill, South Africa are consistent with the formation of a sulfide partial melt. At Broken Hill, Australia, abundant polyphase sulfide melt inclusions (SMINCs) have been identified within garnetite and quartz surrounding remobilised ore. Preliminary examination of garnetites associated with remobilised ore from Broken Hill, South Africa also reveals SMINCs similar to those documented at Broken Hill, Australia. This establishes that sulfide partial melting occurred, at least in the higher metamorphic grade portion of Broken Hill, South Africa. Development of a high temperature heating stage allows reflected light monitoring of submerged SMINCs during heating. The results indicate that quartz-hosted SMINCs from Broken Hill, Australia partially melt at temperatures as low as 420 700° C with total homogenisation occurring at temperatures well below peak metamorphic temperatures (810 700° C). Low melting point chalcophile elements (LMCE) increase in abundance as homogenisation temperatures decrease. This observation along with analysed bulk sulfide melt composition fractionation trends of Pb, Cu, Sb, Ag and Au similar to those observed

  3. Quantifying Coseismic Normal Fault Rupture at the Seafloor: The 2004 Les Saintes Earthquake (Mw 6.3) Along the Roseau Fault (French Antilles)

    NASA Astrophysics Data System (ADS)

    Escartin, J.; Leclerc, F.; Cannat, M.; Petersen, S.; Augustin, N.; Bezos, A.; Bonnemains, D.; Chavagnac, V.; Choi, Y.; Godard, M.; Haaga, K.; Hamelin, C.; Ildefonse, B.; Jamieson, J. W.; John, B. E.; Leleu, T.; Massot-Campos, M.; Mevel, C.; Nomikou, P.; Olive, J. A. L.; Paquet, M.; Rommevaux, C.; Rothenbeck, M.; Steinführer, A.; Tominaga, M.; Triebe, L.; Garcia, R.; Gracias, N.; Feuillet, N.; Deplus, C.

    2014-12-01

    Direct observations of coseismic fault displacement and rupture-related features are essential to understand seismic cycles, to quantify seismic hazard, and to constrain rupture dynamics. They are also needed to trace the paleoseismic history of active faults. Such observations in submarine environments are practically absent, but critical to assess associated tsunami hazard. The ODEMAR cruise studied a ~10 km section of the Roseau Fault (RF) off Les Saintes Islands (Guadeloupe, French Lesser Antilles), a normal fault that generated a Mw 6.3 earthquake in 2004 that triggered a tsunami (<3.5 m of run-up). Microbathymetric data and video observations conducted with the autonomous underwater vehicle ABYSS (GEOMAR) and the remotely operated vehicle VICTOR (IFREMER) allow us to document recent fault-related deformation features. First, the RF hangingwall shows an indurated and ubiquitous rippled sediment layer, locally covered by recent, unconsolidated sediments reworked by currents. Seafloor photomosaics show the indurated layer disrupted by extensional cracks (up to few m long, several 10s of cm wide, ~30 cm deep) along >1 km and by the RF scarp base, that are certainly very young as they are not covered by unconsolidated sediments. Second, video imagery reveals well-preserved, subvertical and polished fault planes exposed at the RF scarp base. Videomosacing and video derived 3D terrain models of a fault outcrop (~12 m long, ~5 m high) reveal on the fault plane a thin, continuous line of unconsolidated sediment sub-parallel to and 10s' of cm above the fault/sediment contact. The line represents the paleo-fault/sediment contact prior to a very recent displacement event, as strong currents in the area would otherwise have washed out the sediment. The fault surface above this line is rougher than that below it. Based on the apparent young age of these features, and given the recurrence time of seismic events along the RF (hundreds to a few thousands of years for Mw 6

  4. Effect of abyssal circulation changes on Oligocene to Miocene benthic foraminifera in the North Atlantic

    SciTech Connect

    Katz, M.E.; Miller, K.G.

    1985-01-01

    Benthic foraminiferal ranges at western North Atlantic Sites 563 and 558 show: 1) gradual Oligocene last occurrences in response to subsidence from the upper to lower abyssal zones; 2) a preponderance of extinctions in the early middle Miocene (about 15.5-13.5 Ma). Comparison of relative and absolute abundance changes at Site 563 sows that percentages of some taxa (e.g. Nuttallides umbonifera) reliably reflect their accumulations while percentages of others vary independently. Regional abundance changes include: 1) maxima N. umbonifera in the middle Oligocene of the deepest sites (10 and 119); 2) increased Planulina wuellerstorfi in the early middle Miocene; 3) increased N. umbonifera in the late middle Miocene. Seismic stratigraphic and delta/sup 13/C evidence indicates a northern bottom-water source for the North Atlantic throughout much of the Oligocene and Miocene. Benthic foraminifera apparently responded to bottom-water changes inferred from carbon isotopic comparisons. The extinction of relict Paleogene taxa and the ascendancy of P. wuellerstorfi in the middle Miocene apparently correlate with increased advection into the eastern Atlantic, subsidence of the Iceland-Faeroe Ridge and increased North Atlantic carbonate sedimentation. The authors speculate that this faunal reorganization was in response to global ocean chemistry changes resulting from increased ventilation of the North Atlantic.

  5. Distribution and diversity of holothuroids (Echinodermata) on Cascadia Basin and Tufts Abyssal Plain

    NASA Astrophysics Data System (ADS)

    Carney, Robert S.; Carey, Andrew G.

    1982-05-01

    The pattern of diversity, species composition, and inter-sample similarity of the holothuroid fauna was examined for 95 beam trawl samples from below 2000 m on the Cascadia Basin and Tufts Abyssal Plain off Oregon, U.S.A. Abundance as inferred from catch size, diversity, species composition, and zonation all showed major change over the sampled area where there was a depth change. Where depth remained relatively constant across the floor of Cascadia Basin, faunal changes were minor in spite of progressive isolation from land. Overall bathymetric patterns of zonation and diversity were basically like those found for other faunal groups in the deep-sea depth. The distribution of minor species indicated that the holothuroid fauna at the base of the continental slope, the apron of Astoria Fan, and near Cascadia Channel might be slightly different from that at similar depths elsewhere in the sampled area. The marked uniformity of the holothuroid fauna across the basin floor appeared to be restricted to epifaunal sediment-feeding species. Infaunal forms were more abundant at the slope base, similar to previous findings for the macro-infauna.

  6. Abyssal ostracods from the South and Equatorial Atlantic Ocean: Biological and paleoceanographic implications

    USGS Publications Warehouse

    Yasuhara, Moriaki; Cronin, T. M.; Martinez, Arbizu P.

    2008-01-01

    We report the distribution of ostracods from ???5000 m depth from the Southeast and Equatorial Atlantic Ocean recovered from the uppermost 10 cm of minimally disturbed sediments taken by multiple-corer during the R/V Meteor DIVA2 expedition M63.2. Five cores yielded the following major deep-sea genera: Krithe, Henryhowella, Poseidonamicus, Legitimocythere, Pseudobosquetina, and Pennyella. All genera are widely distributed in abyssal depths in the world's oceans and common in Cenozoic deep-sea sediments. The total number of ostracod specimens is higher and ostracod shell preservation is better near the sediment-water interface, especially at the 0-1 cm core depths. Core slices from ???5 to 10 cm were barren or yielded a few poorly preserved specimens. The DIVA2 cores show that deep-sea ostracod species inhabit corrosive bottom water near the carbonate compensation depth (CCD) even though their calcareous valves are rarely preserved as fossils in sediment cores due to postmortem dissolution. Their occurrence at great water depths may partially explain the well-known global distributions of major deep-sea taxa in the world's oceans, although further expeditions using minimal-disturbance sampling devices are needed to fill geographic gaps. ?? 2008 Elsevier Ltd. All rights reserved.

  7. Variability of Total Organic Carbon and Nitrogen in Abyssal Sediments in the Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Garcia, F. J.; Escobar Briones, E.

    2007-05-01

    Marine sediments represent the largest reservoir of carbon on Earth and an important factor in climate change and allow us to understand the role of the deep sea sediments as a reservoir for the organic carbon and the chemical balance of nitrogen in the basin. This study determined the precision (CV < 3%) and accuracy (CV < 3%) of the elemental analysis carried out that described the variability of total organic carbon (TOC) and nitrogen from samples collected at 115 locations during several cruises in a depth interval of 1025 and 3725 m. The average values recorded for abyssal sediment samples in the SW Gulf of Mexico were 0.95% +/- 0.135% for TOC and 0.12% +/- 0.025% for N with a C/N ratio of 7.96 +/- 1.406. Only samples from chemosynthetic locations (i.e. Chapopote asphalt volcano) recorded S in 3.35% +/- 1.503%. The elemental composition of TOC and N is controlled by depth and follows a polynomial pattern; the C/N followed a sigmoid pattern and together with TOC varies with the distance to the coast and depth. The presence of topographic features in the seafloor influence the distribution of TOC and N.

  8. Diversity and distribution of Porifera in the bathyal and abyssal Weddell Sea and adjacent areas

    NASA Astrophysics Data System (ADS)

    Janussen, Dorte; Tendal, Ole Secher

    2007-08-01

    During the ANDEEP I-III expeditions, we obtained a rich and highly diverse sponge collection from the deep Weddell Sea. All the three Poriferan classes, Calcarea, Demospongiae and Hexactinellida, were well represented. Among this material, we have identified a total of 76 species from 47 genera and 30 families. Of these, 17 species (22%) are new to science and 37 (49%) new for the Southern Ocean. Particularly remarkable is the considerable depth of the boundary between bathyal and abyssal sponge faunas. Both Demospongiae and Hexactinellida show a strong shift in their taxonomic composition from a typical shelf assemblage to a more cosmopolitan deep-sea fauna at around 2500 m. Within the Demospongiae, the families Polymastiidae and Cladorhizidae (carnivorous sponges) are particularly abundant and very diverse. The Calcarea are recorded for the first time from the Antarctic deep sea. The type of sampling gear used, especially the epibenthic sledge, was an important factor for the successful collection of deep-sea sponges during the ANDEEP campaigns.

  9. Surprises in abyssal peridotites: implications for melt migration beneath ocean ridges

    NASA Astrophysics Data System (ADS)

    Niu, Y.

    2003-04-01

    Since Mike's two classic papers [1,2], the last 35 years have seen much progress on MORB petrogenesis because of improved experimental/theoretical approaches and because of rapid growth of geochemical database on MORB samples from the global ocean ridge system. Our current understanding of MORB genesis also owes a great deal to the studies [3-5] of abyssal peridotites - interpreted as mantle melting residues for MORB. Recent studies [6,7] have confirmed the complementary relationship between MORB and abyssal peridotites, but also revealed the hidden complexities in these peridotites such as olivine addition [6-8] and melt refertilization [7-9]. These same studies [6,7] have simultaneously excited serious debates on the petrogenesis of abyssal peridotites [10-14]. These debates are actually different views on the same observations: modes and major element compositions of residual minerals, and trace element data on residual clinopyroxene (Cpx) [3-5]. I report here whole-rock ICP-MS trace element data on abyssal peridotites including samples previously studied for Cpx trace elements [5]. Residual Cpx shows highly depleted light rare earth elements (LREEs) with flat-to-elevated middle-heavy REEs (e.g., [Ce]_N = 0.25±0.51 [mean±1σ]; [Yb]_N = 6.09±2.59; [Nd/Sm]_N = 0.29±0.14; [Nd/Dy]_N = 0.14±0.11), which is consistent with varying extents of melt depletion [5]. In contrast, whole-rock data of the same samples [15] show elevated abundances of LREEs with flat to enriched LREE patterns (e.g., [Ce]_N = 0.57±0.74; [Yb]_N, 0.72±0.41; [Nd/Sm]_N = 1.18±0.41; [Nd/Dy]_N = 0.70±0.38). If the constituent Cpx records the melting process, the whole-rock data would suggest post-melting LREE addition. The significant correlations of LREEs with high-field strength elements (HFSEs) (e.g., RCe-Zr = 0.730, RNd-Zr = 0.789, RCe-Nb = 0.836, RNd-Nb = 0.900) suggest that this LREE addition is magmatic refertilization (vs. serpentinization). The observation that this magmatic

  10. Evaluation of abyssal meiobenthos in the eastern central Pacific (Clarion-Clipperton fracture zone)

    NASA Astrophysics Data System (ADS)

    Renaud-Mornant, Jeanne; Gourbault, Nicole

    Meiobenthos were sampled from 17 stations in the abyssal deep-sea system of the central Pacific centered around 14°N, 130°W at depths 4960-5154m, during the Nixo 47 R/V Jean Charcot cruise. Meiofaunal density range from 45-89 ind. 10cm 2. Predominant taxa are nematodes (84-100%) and copepods (0-10%). Rotifera, Polychaeta, and Acarina also occur. Nematodes are uniformly distributed spatially with 45 species or so; Monhysteridae is the dominant taxon, and Syringolaimus sp. (Ironidae) co-occurs faithfully. Low biomass (0.4-70.6μg 10cm 2) are attributed to supposed dwarfism of metazoan meiofauna and very high proportion (60-80%) of juveniles and pre-adult forms. The majority of protozoans and metazoans are detritus- or deposit-feeders; in addition symbiotic associations, coprophagy and gardening activities are frequent. In such an oligotrophic environment, low food supply may limit meiofaunal abundance, biomass and maturation, and to a lesser extent species richness.

  11. Simulated strengthening of the Atlantic Meridional Overturning Circulation in response to abyssal ocean warming around Antarctica

    NASA Astrophysics Data System (ADS)

    Patara, L.; Boning, C. W.

    2013-12-01

    Studies of repeat hydrographic observations have revealed a conspicuous multi-decadal warming, and partly, freshening, of the frigid abyssal ocean waters originating from the fringes of the Antarctic continent. The warming and contraction of Antarctic Bottom Water (AABW) represents one of the most prominent signals of change in Earth's climate and accounts for a substantial fraction of the present global energy and sea level budgets. Here we present a set of ocean model experiments demonstrating that the ongoing loss of AABW also has important dynamical consequences for the large-scale meridional overturning circulation in the Atlantic Ocean. In conjunction with a slowdown of the bottom cell, we find that the upper cell of the Atlantic Meridional Overturning Circulation (AMOC) progressively strengthens in response to changes in density gradients in the deep South Atlantic. Changes in the AMOC are tightly connected to increased meridional heat transport and therefore have a strong influence on global and regional climate patterns in the North Atlantic. The simulations suggest that the AABW-induced strengthening of the AMOC is already extending into the North Atlantic, progressing at a rate of about 0.2 Sv per decade, implying that the process may need to be taken into account in projections of future North Atlantic climate.

  12. Histological, histochemical and immunohistochemical study on the growing oocytes of the abyssal teleost Hoplostethus mediterraneus (V).

    PubMed

    Calabro, Concetta; Albanese, Maria Pia; Bertuccio, Clara; Licata, Aurelio; Gentile, Nunzia

    2008-01-01

    The oocytes of the abyssal Teleost, Hoplostethus mediterraneus were studied. Four stages of growth were observed and the oocytes of all the stages were surrounded by follicular cells and had several nucleoli in the nucleus. In the oocytes of the II degrees stage, vacuoles without contents, in oocytes of the III degrees stage several vacuoles with a basophilic contents and small yolk globules were identified. General and basic proteins, ribonucleoproteins, acid proteoglycans with -COOH groups were recognized in the cytoplasm, in the nucleoli of oocytes in the II degrees stage and in the vacuolar contents of oocytes in the III degrees stage. In the follicular cells, in the pellucid zone, in the yolk globules, from their beginning, glycoproteins were present. Positivity, for all lectins used, was revealed in the follicular cells and in the four stages of oocytes growth. alpha-D-glucose and alpha-D-mannose binding sites were in the pellucid zone and in the initial yolk globules. In the lather galactose and beta-N-acetyl glucosamine were present too. nNOS and VIP immunopositivity revealed at the periphery of the cytoplasm and at network of nerve fibres between oocytes, suggests NO is involved in a mechanism of regulation of the gametogenesis and of the spawning. PMID:18296271

  13. Community change in the variable resource habitat of the abyssal northeast Pacific.

    PubMed

    Ruhl, Henry A

    2008-04-01

    Research capable of differentiating resource-related community-level change from random ecological drift in natural systems has been limited. Evidence for nonrandom, resource-driven change is presented here for an epibenthic megafauna community in the abyssal northeast Pacific Ocean from 1989 to 2004. The sinking particulate organic carbon food supply is linked not only to species-specific abundances, but also to species composition and equitability. Shifts in rank abundance distributions (RADs) and evenness, from more to less equitable, correlated to increased food supply during La Niña phases of the El Niño Southern Oscillation. The results suggest that each taxon exhibited a differential response to a sufficiently low dimension resource, which led to changes in community composition and equitability. Thus the shifts were not likely due to random ecological drift. Although the community can undergo population-level variations of one or more orders of magnitude, and the shape of the RADs was variable, the organization retained a significant consistency, providing evidence of limits for such changes. The growing evidence for limited resource-driven changes in RADs and evenness further emphasizes the potential importance of temporally variable disequilibria in understanding why communities have certain basic attributes. PMID:18481524

  14. Photo-real rendering of bioluminescence and iridescence in creatures from the abyss

    NASA Astrophysics Data System (ADS)

    Prusten, Mark

    2008-08-01

    The generation of photo-real renderings of bioluminescence is developed for creatures from the abyss. Bioluminescence results from a chemical reaction with examples found in deep-sea marine environments including: algae, copepods, jellyfish, squid, and fish. In bioluminescence, the excitation energy is supplied by a chemical reaction, not by a source of light. The greatest transparency window in seawater is in the blue region of the visible spectrum. From small creatures like single-cell algae, to large species of siphonophore Praya dubia (40m), luminescent phenomena can be produced by mechanical excitement from disturbances of objects passing by. Deep sea fish, like the Pacific Black Dragonfish are covered with photophores along the upper and lower surfaces which emits light when disturbed. Other animals like small squids have several different types of light organs oscillating at different rates. Custom shaders and material phenomena incorporate indirect lighting like: global illumination, final gathering, ambient occlusion and subsurface scattering to provide photo real images. Species like the Hydomedusae jellyfish, produce colors that are also generated by iridescence of thin tissues. The modeling and rendering of these tissues requires thin film multilayer stacks. These phenomena are simulated by semi-rigid body dynamics in a procedural animation environment. These techniques have been applied to develop spectral rendering of scenes outside the normal visible window in typical computer animation render engines.

  15. Mineralogy of the mid-ocean-ridge basalt source from neodymium isotopic composition of abyssal peridotites.

    PubMed

    Salters, Vincent J M; Dick, Henry J B

    2002-07-01

    Inferring the melting process at mid-ocean ridges, and the physical conditions under which melting takes place, usually relies on the assumption of compositional similarity between all mid-ocean-ridge basalt sources. Models of mantle melting therefore tend to be restricted to those that consider the presence of only one lithology in the mantle, peridotite. Evidence from xenoliths and peridotite massifs show that after peridotite, pyroxenite and eclogite are the most abundant rock types in the mantle. But at mid-ocean ridges, where most of the melting takes place, and in ophiolites, pyroxenite is rarely found. Here we present neodymium isotopic compositions of abyssal peridotites to investigate whether peridotite can indeed be the sole source for mid-ocean-ridge basalts. By comparing the isotopic compositions of basalts and peridotites at two segments of the southwest Indian ridge, we show that a component other than peridotite is required to explain the low end of the (143)Nd/(144)Nd variations of the basalts. This component is likely to have a lower melting temperature than peridotite, such as pyroxenite or eclogite, which could explain why it is not observed at mid-ocean ridges. PMID:12097907

  16. Extensional reactivation of the Chocolate Mountains subduction thrust in the Gavilan Hills of southeastern California

    USGS Publications Warehouse

    Oyarzabal, F.R.; Jacobson, C.E.; Haxel, G.B.

    1997-01-01

    The NE vergent Chocolate Mountains fault of south-eastern California has been interpreted as either a subduction thrust responsible for burial and prograde metamorphism of the ensimatic Orocopia Schist or as a normal fault involved in the exhumation of the schist. Our detailed structural analysis in the Gavilan Hills area provides new evidence to confirm the latter view. A zone of deformation is present at the top of the Orocopia Schist in which lineations are parallel to those in the upper plate of the Chocolate Mountains fault but oblique to ones at relatively deep levels in the schist. Both the Orocopia Schist and upper plate contain several generations of shear zones that show a transition from crystalloblastic through mylonitic to cataclastic textures. These structures formed during retrograde metamorphism and are considered to record the exhumation of the Orocopia Schist during early Tertiary time as a result of subduction return flow. The Gatuna fault, which places low-grade, supracrustal metasediments of the Winterhaven Formation above the gneisses of the upper plate, also seems to have been active at this time. Final unroofing of the Orocopia Schist occurred during early to middle Miocene regional extension and may have involved a second phase of movement on the Gatuna fault. Formation of the Chocolate Mountains fault during exhumation indicates that its top-to-the-NE sense of movement provides no constraint on the polarity of the Orocopia Schist subduction zone. This weakens the case for a previous model involving SW dipping subduction, while providing support for the view that the Orocopia Schist is a correlative of the Franciscan Complex.

  17. Isolability of faults in sensor fault diagnosis

    NASA Astrophysics Data System (ADS)

    Sharifi, Reza; Langari, Reza

    2011-10-01

    A major concern with fault detection and isolation (FDI) methods is their robustness with respect to noise and modeling uncertainties. With this in mind, several approaches have been proposed to minimize the vulnerability of FDI methods to these uncertainties. But, apart from the algorithm used, there is a theoretical limit on the minimum effect of noise on detectability and isolability. This limit has been quantified in this paper for the problem of sensor fault diagnosis based on direct redundancies. In this study, first a geometric approach to sensor fault detection is proposed. The sensor fault is isolated based on the direction of residuals found from a residual generator. This residual generator can be constructed from an input-output or a Principal Component Analysis (PCA) based model. The simplicity of this technique, compared to the existing methods of sensor fault diagnosis, allows for more rational formulation of the isolability concepts in linear systems. Using this residual generator and the assumption of Gaussian noise, the effect of noise on isolability is studied, and the minimum magnitude of isolable fault in each sensor is found based on the distribution of noise in the measurement system. Finally, some numerical examples are presented to clarify this approach.

  18. Geodetic observations of fault creep in the Imperial Valley: hidden faults, earthquake hazard and implications for frictional properties

    NASA Astrophysics Data System (ADS)

    Lindsey, E. O.; Fialko, Y. A.

    2014-12-01

    We present new observations of the pattern of fault creep and interseismic deformation in the Imperial Valley, California using a combination of multiple InSAR viewing geometries and survey-mode GPS. We combine more than 100 survey-mode GPS velocities (Crowell et al., 2013) with Envisat InSAR observations from descending tracks 84 and 356 and ascending tracks 77 and 306 (149 total acquisitions), processed using the Stanford Method for Persistent Scatterers (StaMPS) package (Hooper et al., 2007). The result is a dense map of surface velocities across the Imperial fault and surrounding areas. The data suggest that a previously little-known extension of the Superstition Hills fault through the town of El Centro may accommodate a significant portion of the slip previously attributed to the Imperial Fault. We investigate a suite of possible models for the transfer of this slip to the Imperial and Cerro Prieto faults to the south, yielding a range of plausible hazard scenarios. Finally, we compare the geodetic data to models of earthquake cycles with rate- and state-dependent friction to assess the implications for creep depth, moment accumulation rate, and recurrence interval of large events on these faults.

  19. Genetic and morphological divergences in the cosmopolitan deep-sea amphipod Eurythenes gryllus reveal a diverse abyss and a bipolar species.

    PubMed

    Havermans, Charlotte; Sonet, Gontran; d'Udekem d'Acoz, Cédric; Nagy, Zoltán T; Martin, Patrick; Brix, Saskia; Riehl, Torben; Agrawal, Shobhit; Held, Christoph

    2013-01-01

    Eurythenes gryllus is one of the most widespread amphipod species, occurring in every ocean with a depth range covering the bathyal, abyssal and hadal zones. Previous studies, however, indicated the existence of several genetically and morphologically divergent lineages, questioning the assumption of its cosmopolitan and eurybathic distribution. For the first time, its genetic diversity was explored at the global scale (Arctic, Atlantic, Pacific and Southern oceans) by analyzing nuclear (28S rDNA) and mitochondrial (COI, 16S rDNA) sequence data using various species delimitation methods in a phylogeographic context. Nine putative species-level clades were identified within E. gryllus. A clear distinction was observed between samples collected at bathyal versus abyssal depths, with a genetic break occurring around 3,000 m. Two bathyal and two abyssal lineages showed a widespread distribution, while five other abyssal lineages each seemed to be restricted to a single ocean basin. The observed higher diversity in the abyss compared to the bathyal zone stands in contrast to the depth-differentiation hypothesis. Our results indicate that, despite the more uniform environment of the abyss and its presumed lack of obvious isolating barriers, abyssal populations might be more likely to show population differentiation and undergo speciation events than previously assumed. Potential factors influencing species' origins and distributions, such as hydrostatic pressure, are discussed. In addition, morphological findings coincided with the molecular clades. Of all specimens available for examination, those of the bipolar bathyal clade seemed the most similar to the 'true' E. gryllus. We present the first molecular evidence for a bipolar distribution in a macro-benthic deep-sea organism. PMID:24086322

  20. Genetic and Morphological Divergences in the Cosmopolitan Deep-Sea Amphipod Eurythenes gryllus Reveal a Diverse Abyss and a Bipolar Species

    PubMed Central

    Havermans, Charlotte; Sonet, Gontran; d’Udekem d’Acoz, Cédric; Nagy, Zoltán T.; Martin, Patrick; Brix, Saskia; Riehl, Torben; Agrawal, Shobhit; Held, Christoph

    2013-01-01

    Eurythenes gryllus is one of the most widespread amphipod species, occurring in every ocean with a depth range covering the bathyal, abyssal and hadal zones. Previous studies, however, indicated the existence of several genetically and morphologically divergent lineages, questioning the assumption of its cosmopolitan and eurybathic distribution. For the first time, its genetic diversity was explored at the global scale (Arctic, Atlantic, Pacific and Southern oceans) by analyzing nuclear (28S rDNA) and mitochondrial (COI, 16S rDNA) sequence data using various species delimitation methods in a phylogeographic context. Nine putative species-level clades were identified within E. gryllus. A clear distinction was observed between samples collected at bathyal versus abyssal depths, with a genetic break occurring around 3,000 m. Two bathyal and two abyssal lineages showed a widespread distribution, while five other abyssal lineages each seemed to be restricted to a single ocean basin. The observed higher diversity in the abyss compared to the bathyal zone stands in contrast to the depth-differentiation hypothesis. Our results indicate that, despite the more uniform environment of the abyss and its presumed lack of obvious isolating barriers, abyssal populations might be more likely to show population differentiation and undergo speciation events than previously assumed. Potential factors influencing species’ origins and distributions, such as hydrostatic pressure, are discussed. In addition, morphological findings coincided with the molecular clades. Of all specimens available for examination, those of the bipolar bathyal clade seemed the most similar to the ‘true’ E. gryllus. We present the first molecular evidence for a bipolar distribution in a macro-benthic deep-sea organism. PMID:24086322

  1. A Controllable Earthquake Rupture Experiment on the Homestake Fault

    NASA Astrophysics Data System (ADS)

    Germanovich, L. N.; Murdoch, L. C.; Garagash, D.; Reches, Z.; Martel, S. J.; Gwaba, D.; Elsworth, D.; Lowell, R. P.; Onstott, T. C.

    2010-12-01

    Fault-slip is typically simulated in the laboratory at the cm-to-dm scale. Laboratory results are then up-scaled by orders of magnitude to understand faulting and earthquakes processes. We suggest an experimental approach to reactivate faults in-situ at scales ~10-100 m using thermal techniques and fluid injection to modify in situ stresses and the fault strength to the point where the rock fails. Mines where the modified in-situ stresses are sufficient to drive faulting, present an opportunity to conduct such experiments. During our recent field work in the former Homestake gold mine in the northern Black Hills, South Dakota, we found a large fault present on multiple mine levels. The fault is subparallel to the local foliation in the Poorman formation, a Proterozoic metamorphic rock deformed into regional-scale folds with axes plunging ~40° to the SSE. The fault extends at least 1.5 km along strike and dip, with a center ~1.5 km deep. It strikes ~320-340° N, dips ~45-70° NE, and is recognized by a ~0.3-0.5 m thick distinct gouge that contains crushed host rock and black material that appears to be graphite. Although we could not find clear evidence for fault displacement, secondary features suggest that it is a normal fault. The size and distinct structure of this fault make it a promising target for in-situ experimentation of fault strength, hydrological properties, and slip nucleation processes. Most earthquakes are thought to be the result of unstable slip on existing faults, Activation of the Homestake fault in response to the controlled fluid injection and thermally changing background stresses is likely to be localized on a crack-like patch. Slow patch propagation, moderated by the injection rate and the rate of change of the background stresses, may become unstable, leading to the nucleation of a small earthquake (dynamic) rupture. This controlled instability is intimately related to the dependence of the fault strength on the slip process and has been

  2. Paleoseismic displacement history, Coachella Valley segment, San Andreas fault

    NASA Astrophysics Data System (ADS)

    Williams, P. L.

    2009-12-01

    This paper examines individual earthquake displacements and slip curves for the southern segment of the San Andreas fault. In prior work, detailed geomorphic slip evidence (features offset up to ~20 meters right-laterally) were inventoried along the southern 50 km (Bombay Beach to Thermal) of the Coachella Valley Segment (CVS). Compilation of that survey, and current work indicate that the latest 5 events produced moderate offsets, averaging 3-4 meters from Durmid Hill (adjacent to the Salton Sea) through the central Indio Hills (adjacent to Palm Desert). Streams exhibiting cumulative offset of 15 to 18 meters are interpreted to record five events, with locally higher values obtained in the southern Mecca Hills and central Indio Hills. Stream displacements of 21 to 24 and 25 to 28 meters have been documented at a small number of sites. The presence of larger values, and absence of intervening values, indicates these events likely were characterized by offsets larger than 3-4 meters. Addressing the contribution to total offset from fault creep is especially important to characterize slip-per-event on the CVS, since creep contributes up to 20 to 30% of the long-term slip rate there (Sieh and Williams 1990). While creep probably can't be discriminated from seismic offset in geomorphic study of multi-event fault offsets, the consistency of field evidence indicates that creep may be a neutral or minor factor in interpreting the offset record: i.e., the surface slip in a given earthquake cycle, while a sum of seismic + postseismic surface slip, approximates total seismogenic slip at depth. In the present open interval, for example, the strongest signal for prior event slip is ~3.5m. 1-1.5m of this is presumed to be postseismic creep (ibid). Thus the latest seismic surface slip was probably about 2-2.5m, and the latest seismogenic rupture (at depth) was probably in the range of 3-3.5 m, and 1-1.5m of this occurred as postseismic slip plus creep at the surface. Prior event

  3. Uranium series dating of Allan Hills ice

    NASA Technical Reports Server (NTRS)

    Fireman, E. L.

    1986-01-01

    Uranium-238 decay series nuclides dissolved in Antarctic ice samples were measured in areas of both high and low concentrations of volcanic glass shards. Ice from the Allan Hills site (high shard content) had high Ra-226, Th-230 and U-234 activities but similarly low U-238 activities in comparison with Antarctic ice samples without shards. The Ra-226, Th-230 and U-234 excesses were found to be proportional to the shard content, while the U-238 decay series results were consistent with the assumption that alpha decay products recoiled into the ice from the shards. Through this method of uranium series dating, it was learned that the Allen Hills Cul de Sac ice is approximately 325,000 years old.

  4. A generalized Hill-Wheeler ansatz

    NASA Astrophysics Data System (ADS)

    Nuñez, J.; Esebbag, C.; Martin, M. T.; Rebollo, L.; Plastino, A.

    1984-06-01

    The Hill-Wheeler ansatz for the total wave function, within the Generator Coordinate Method framework, is generalized by recourse to the theory of distributions. The ensuing approach allows one to obtain a basis that spans the collective subspace, without having to deal explicitly with the eigenvectors and eigenvalues of the overlap kernel. Applications to an exactly soluble model and anharmonic vibrations illustrate the present treatment.

  5. Possible Meteorites in the Martian Hills

    NASA Technical Reports Server (NTRS)

    2006-01-01

    From its winter outpost at 'Low Ridge' inside Gusev Crater, NASA's Mars Exploration Rover Spirit took this spectacular, color mosaic of hilly, sandy terrain and two potential iron meteorites. The two light-colored, smooth rocks about two-thirds of the way up from the bottom of the frame have been labeled 'Zhong Shan' and 'Allan Hills.'

    The two rocks' informal names are in keeping with the rover science team's campaign to nickname rocks and soils in the area after locations in Antarctica. Zhong Shang is an Antarctic base that the People's Republic of China opened on Feb. 26, 1989, at the Larsemann Hills in Prydz Bay in East Antarctica. Allan Hills is a location where researchers have found many Martian meteorites, including the controversial ALH84001, which achieved fame in 1996 when NASA scientists suggested that it might contain evidence for fossilized extraterrestrial life. Zhong Shan was the given name of Dr. Sun Yat-sen (1866-1925), known as the 'Father of Modern China.' Born to a peasant family in Guangdong, Sun moved to live with his brother in Honolulu at age 13 and later became a medical doctor. He led a series of uprisings against the Qing dynasty that began in 1894 and eventually succeeded in 1911. Sun served as the first provisional president when the Republic of China was founded in 1912.

    The Zhong Shan and Allan Hills rocks, at the left and right, respectively, have unusual morphologies and miniature thermal emission spectrometer signatures that resemble those of a rock known as 'Heat Shield' at the Meridiani site explored by Spirit's twin, Opportunity. Opportunity's analyses revealed Heat Shield to be an iron meteorite.

    Spirit acquired this approximately true-color image on the rover's 872nd Martian day, or sol (June 16, 2006), using exposures taken through three of the panoramic camera's filters, centered on wavelengths of 600 nanometers, 530 nanometers, and 480 nanometers.

  6. Hill Ciphers over Near-Fields

    ERIC Educational Resources Information Center

    Farag, Mark

    2007-01-01

    Hill ciphers are linear codes that use as input a "plaintext" vector [p-right arrow above] of size n, which is encrypted with an invertible n x n matrix E to produce a "ciphertext" vector [c-right arrow above] = E [middle dot] [p-right arrow above]. Informally, a near-field is a triple [left angle bracket]N; +, *[right angle bracket] that…

  7. SRTM Stereo Pair: Haro and Kas Hills, India

    NASA Technical Reports Server (NTRS)

    2001-01-01

    On January 26, 2001 the Kachchh region in western India suffered the most deadly earthquake in India's history. This stereoscopic view of landforms northeast of the city of Bhuj depicts geologic structures that are of interest in the study the tectonic processes that may have led to that earthquake. However, preliminary field studies indicate that these structures are composed of Mesozoic rocks that are overlain by younger rocks showing little deformation. Thus these structures may be old, not actively growing, and not directly related to the recent earthquake.

    The Haro Hills are on the left and the Kas Hills are on the right. The Haro Hills are an 'anticline,' which is an upwardly convex elongated fold of layered rocks. The anticline is distinctly ringed by an erosion resistant layer of sandstone. The east-west orientation of the anticline may relate to the crustal compression that has occurred during India's northward movement toward, and collision with, Asia. In contrast, the largest of the Kas Hills appears to be a tilted (to the south) and faulted (on the north) block of layered rocks. Also seen here, the curvilinear ridge trending toward the southwest from the image center is an erosion resistant 'dike,' which is an igneous intrusion into older 'host' rocks along a fault plane or other crack. The dike also appears to extend northeast from the image center as a dark line having very little topography. Its location between the tilted block and a smaller anticline to the north (directly east of the larger anticline) probably indicates that the dike fills the fault that separates these contrasting geologic structures. These features are simple examples of how digital elevation data can stereoscopically enhance satellite imagery to provide a direct input to geologic studies.

    This stereoscopic image was generated by draping a Landsat satellite image (taken just two weeks after the earthquake) over a preliminary Shuttle Radar Topography Mission (SRTM

  8. SRTM Stereo Pair: Haro and Kas Hills, India

    NASA Technical Reports Server (NTRS)

    2001-01-01

    On January 26, 2001 the Kachchh region in western India suffered the most deadly earthquake in India's history. This stereoscopic view of landforms northeast of the city of Bhuj depicts geologic structures that are of interest in the study the tectonic processes that may have led to that earthquake. However, preliminary field studies indicate that these structures are composed of Mesozoic rocks that are overlain by younger rocks showing little deformation. Thus these structures may be old, not actively growing, and not directly related to the recent earthquake.

    The Haro Hills are on the left and the Kas Hills are on the right. The Haro Hills are an 'anticline,' which is an upwardly convex elongated fold of layered rocks. The anticline is distinctly ringed by an erosion resistant layer of sandstone. The east-west orientation of the anticline may relate to the crustal compression that has occurred during India's northward movement toward, and collision with, Asia. In contrast, the largest of the Kas Hills appears to be a tilted (to the south) and faulted (on the north) block of layered rocks. Also seen here, the curvilinear ridge trending toward the southwest from the image center is an erosion resistant 'dike,' which is an igneous intrusion into older 'host' rocks along a fault plane or other crack. The dike also appears to extend northeast from the image center as a dark line having very little topography. Its location between the tilted block and a smaller anticline to the north (directly east of the larger anticline) probably indicates that the dike fills the fault that separates these contrasting geologic structures. These features are simple examples of how digital elevation data can stereoscopically enhance satellite imagery to provide a direct input to geologic studies.

    This stereoscopic image was generated by draping a Landsat satellite image (taken just two weeks after the earthquake) over a preliminary Shuttle Radar Topography Mission (SRTM

  9. The Rocks of the Columbia Hills

    NASA Technical Reports Server (NTRS)

    Squyres, Steven W.; Arvidson, Raymond E.; Blaney, Diana L.; Clark, Benton C.; Crumpler, Larry; Farrand, William H.; Gorevan, Stephen; Herkenhoff, Kenneth; Hurowitz, Joel; Kusack, Alastair; McSween, Harry Y.; Ming, Douglas W.; Morris, Richard V.; Ruff, Steven W.; Wang, Alian; Yen, Albert

    2006-01-01

    The Mars Exploration Rover Spirit has identified five distinct rock types in the Columbia Hills of Gusev crater. Clovis Class rock is a poorly-sorted clastic rock that has undergone substantial aqueous alteration. We interpret it to be aqueously-altered ejecta deposits formed by impacts into basaltic materials. Wishstone Class rock is also a poorly-sorted clastic rock that has a distinctive chemical composition that is high in Ti and P and low in Cr. Wishstone Class rock may be pyroclastic in origin. Peace Class rock is a sedimentary material composed of ultramafic sand grains cemented by significant quantities of Mg- and Ca-sulfates. Peace Class rock may have formed when water briefly saturated the ultramafic sands, and evaporated to allow precipitation of the sulfates. Watchtower Class rocks are similar chemically to Wishstone Class rocks, and have undergone widely varying degrees of near-isochemical aqueous alteration. They may also be ejecta deposits, formed by impacts into Wishstone-rich materials and altered by small amounts of water. Backstay Class rocks are basalt/trachybasalt lavas that were emplaced in the Columbia Hills after the other rock classes were, either as impact ejecta or by localized volcanic activity. The geologic record preserved in the rocks of the Columbia Hills reveals a period very early in martian history in which volcanic materials were widespread, impact was a dominant process, and water was commonly present.

  10. Three-dimensional fault drawing

    SciTech Connect

    Dongan, L. )

    1992-01-01

    In this paper, the author presents a structure interpretation based on three-dimensional fault drawing. It is required that fault closure must be based on geological theory, spacial plotting principle and restrictions in seismic exploration. Geological structure can be well ascertained by analysing the shapes and interrelation of the faults which have been drawn through reasonable fault point closure and fault point correlation. According to this method, the interrelation of fault points is determined by first closing corresponding fault points in intersecting sections, then reasonably correlating the relevant fault points. Fault point correlation is not achieved in base map, so its correctness can be improved greatly. Three-dimensional fault closure is achieved by iteratively revising. The closure grid should be densified gradually. The distribution of major fault system is determined prior to secondary faults. Fault interpretation by workstation also follows this procedure.

  11. Investigation of Quaternary slip rates along the Banning strand of the southern San Andreas Fault near San Gorgonio Pass

    NASA Astrophysics Data System (ADS)

    Gold, P. O.; Behr, W. M.; Rood, D.; Kendrick, K. J.; Rockwell, T. K.; Sharp, W. D.

    2013-12-01

    Present-day Pacific-North American relative plate motion in southern California is shared primarily between the San Jacinto and San Andreas faults. At the north end of the Coachella Valley, the San Andreas fault splits into the Banning and Mission Creek strands, which are sub-parallel to each other within the Indio Hills. Northwest of the Indio Hills, the Mission Creek fault diverges from the Banning and continues northwest toward the southeastern San Bernardino Mountains, but loses surface expression beneath Quaternary alluvial deposits in Morongo Wash. The Banning fault, upon exiting the Indio Hills, is deflected toward the west and transitions into a structurally complex fault zone at San Gorgonio Pass, where it is delineated by thrust scarps in Holocene alluvium. The slip rates of the Banning and Mission Creek fault strands northwest of the Indio Hills and southeast of San Gorgonio Pass are presently unconstrained, but understanding how slip is partitioned between these two strands is critical to southern California earthquake forecasting efforts. Here we present preliminary slip rate data for the Banning fault ~2 km southeast of San Gorgonio Pass at Devers Hill. Using the B4 LiDAR as a base, we have mapped the extents of three truncated and offset alluvial fan deposits, which we have differentiated based on both field and remote (LiDAR- and air photo-based) observations of texture: in particular, the distribution of different clast sizes, pavement and soil development, and color and appearance. To confirm across-fault correlation of the displaced deposits, we have measured 26 cosmogenic Be-10 ages from boulders and cobble samples taken from each of the three fan surfaces on both sides of the fault. One debris flow deposit (Q2a) has been dated to ~80 ka, and appears to be offset 1.6-2.2 km, though confirming this reconstruction will depend on future excavations and uranium-series dating of soil carbonate. A second debris flow deposit (Q2b), for which ages are

  12. How Faults Shape the Earth.

    ERIC Educational Resources Information Center

    Bykerk-Kauffman, Ann

    1992-01-01

    Presents fault activity with an emphasis on earthquakes and changes in continent shapes. Identifies three types of fault movement: normal, reverse, and strike faults. Discusses the seismic gap theory, plate tectonics, and the principle of superposition. Vignettes portray fault movement, and the locations of the San Andreas fault and epicenters of…

  13. Response of deformation patterns to reorganizations of the southern San Andreas fault system since ca. 1.5 Ma

    NASA Astrophysics Data System (ADS)

    Cooke, M. L.; Fattaruso, L.; Dorsey, R. J.; Housen, B. A.

    2015-12-01

    Between ~1.5 and 1.1 Ma, the southern San Andreas fault system underwent a major reorganization that included initiation of the San Jacinto fault and termination of slip on the extensional West Salton detachment fault. The southern San Andreas fault itself has also evolved since this time, with several shifts in activity among fault strands within San Gorgonio Pass. We use three-dimensional mechanical Boundary Element Method models to investigate the impact of these changes to the fault network on deformation patterns. A series of snapshot models of the succession of active fault geometries explore the role of fault interaction and tectonic loading in abandonment of the West Salton detachment fault, initiation of the San Jacinto fault, and shifts in activity of the San Andreas fault. Interpreted changes to uplift patterns are well matched by model results. These results support the idea that growth of the San Jacinto fault led to increased uplift rates in the San Gabriel Mountains and decreased uplift rates in the San Bernardino Mountains. Comparison of model results for vertical axis rotation to data from paleomagnetic studies reveals a good match to local rotation patterns in the Mecca Hills and Borrego Badlands. We explore the mechanical efficiency at each step in the evolution, and find an overall trend toward increased efficiency through time. Strain energy density patterns are used to identify regions of off-fault deformation and potential incipient faulting. These patterns support the notion of north-to-south propagation of the San Jacinto fault during its initiation. The results of the present-day model are compared with microseismicity focal mechanisms to provide additional insight into the patterns of off-fault deformation within the southern San Andreas fault system.

  14. Determining the origin of enigmatic bedrock structures using apatite (U-Th)/He thermochronology: Alabama and Poverty Hills, Owens Valley, California

    NASA Astrophysics Data System (ADS)

    Ali, G. A.; Reiners, P. W.; Ducea, M.

    2008-12-01

    The Alabama and Poverty Hills are enigmatic, topographic highs of crystalline basement surrounded by Neogene sediments in Owens Valley, California. The 150-km long Owens Valley, the westernmost graben of the Basin and Range Province, initiated at about 3 Ma, creating ~2-4 km of vertical relief from the Sierra Nevada and White/Inyos crests to the valley floor. Along the valley, the active right-lateral Owens Valley Fault Zone (OVFZ) accommodates a significant portion of Pacific-North American plate motion, creating an oblique dextral fault zone, with localized transpression along minor left-stepovers. The dominantly granitic Mesozoic rocks of the Alabama Hills are bounded by the OVFZ to the east, and the granitic and metavolcanic Mesozoic rocks of the Poverty Hills are located along an apparent 3-km left stepover of the OVFZ. The tectonic origin and geodynamic significance of both these structures are not known, but previously published hypotheses include: 1) transpressional uplifts as OVFZ-related flower structures; 2) down-dropped normal fault blocks; and 3) giant landslides from adjacent ranges. We measured apatite (U-Th)/He ages on 15 samples from the Alabama and Poverty Hills to understand the history of shallow crustal exhumation of these structures, and to potentially correlate them to rocks from adjacent ranges. Apatite He dating typically yields cooling ages corresponding to closure temperatures of ~55-65 °C, corresponding roughly to depths of ~2-3 km in the crust. The majority of apatite He ages from the Alabama Hills ranged from 58-70 Ma, but the far eastern, and lowest elevation sample showed ages of 51-55 Ma. The Poverty Hills shows younger ages of 40-65 Ma and no recognizable spatial pattern. Although the data do not conclusively rule out a transpressional uplift origin of the Poverty Hills, the rocks within them could not have been exhumed from depths greater than ~2-3 km in Owens Valley. Data from both structures are most consistent with down

  15. Fault detection and fault tolerance in robotics

    NASA Technical Reports Server (NTRS)

    Visinsky, Monica; Walker, Ian D.; Cavallaro, Joseph R.

    1992-01-01

    Robots are used in inaccessible or hazardous environments in order to alleviate some of the time, cost and risk involved in preparing men to endure these conditions. In order to perform their expected tasks, the robots are often quite complex, thus increasing their potential for failures. If men must be sent into these environments to repair each component failure in the robot, the advantages of using the robot are quickly lost. Fault tolerant robots are needed which can effectively cope with failures and continue their tasks until repairs can be realistically scheduled. Before fault tolerant capabilities can be created, methods of detecting and pinpointing failures must be perfected. This paper develops a basic fault tree analysis of a robot in order to obtain a better understanding of where failures can occur and how they contribute to other failures in the robot. The resulting failure flow chart can also be used to analyze the resiliency of the robot in the presence of specific faults. By simulating robot failures and fault detection schemes, the problems involved in detecting failures for robots are explored in more depth.

  16. Confidence Hills Mineralogy and Chemin Results from Base of Mt. Sharp, Pahrump Hills, Gale Crater, Mars

    NASA Technical Reports Server (NTRS)

    Cavanagh, P. D.; Bish, D. L.; Blake, D. F.; Vaniman, D. T.; Morris, R. V.; Ming, D. W.; Rampe, E. B.; Achilles, C. N.; Chipera, S. J.; Treiman, A. H.; Downs, R. T.; Morrison, S. M.; Fendrich, K. V.; Yen, A. S.; Grotzinger, J.; Crisp, J. A.; Bristow, T. F.; Sarrazin, P. C.; Farmer, J. D.; Des Marais, D. J.; Stolper, E. M.; Morookian, J. M.; Wilson, M. A.; Spanovich, N.; Anderson, R. C.

    2015-01-01

    The Mars Science Laboratory (MSL) rover Curiosity recently completed its fourth drill sampling of sediments on Mars. The Confidence Hills (CH) sample was drilled from a rock located in the Pahrump Hills region at the base of Mt. Sharp in Gale Crater. The CheMin X-ray diffractometer completed five nights of analysis on the sample, more than previously executed for a drill sample, and the data have been analyzed using Rietveld refinement and full-pattern fitting to determine quantitative mineralogy. Confidence Hills mineralogy has several important characteristics: 1) abundant hematite and lesser magnetite; 2) a 10 angstrom phyllosilicate; 3) multiple feldspars including plagioclase and alkali feldspar; 4) mafic silicates including forsterite, orthopyroxene, and two types of clinopyroxene (Ca-rich and Ca-poor), consistent with a basaltic source; and 5) minor contributions from sulfur-bearing species including jarosite.

  17. Abyssal and deep circulation in the Eastern Mediterranean Sea (Ionian Sea)

    NASA Astrophysics Data System (ADS)

    Artale, Vincenzo; Bensi, Manuel; Falcini, Federico; Marullo, Salvatore; Rubino, Angelo

    2016-04-01

    In the mid-1990s, experimental evidences on the Eastern Mediterranean Transient (EMT) were presented and it was shown that the Mediterranean abyssal circulation is not in a steady state but can be subjected to episodic sudden changes (Roether et al., 1996). In the last 10 years the Ionian Sea, the central and deepest part of the Mediterranean Sea, was subjected to relevant scientific interests from a theoretical and experimental point of view. Among these, there is the discovery of the BiOS (Bimodal Oscillating System), one new mechanism that drives a periodic (almost decadal) redistribution of surface and subsurface waters in the Eastern Mediterranean, with considerable feedbacks in the variability of the deep-water formation both in the southern Adriatic and in the Levantine and Aegean sub-basins (Gačić et al., 2010). In the Ionian Sea, numerous recent observational campaigns have been conducted to investigate the behaviour of deep and abyssal waters, at depths between 2000-4000m that are comparable to the mean global ocean depth (Rubino and Hainbucher, 2007; Bensi et al., 2013). There, advection, diffusion and vertical stability of the water masses can assume an important role on the internal quasi-periodical variability, creating the preconditions for catastrophic events such as the EMT or reversals of the Ionian circulation (Pisacane et al., 2006). Since there are no significant deep heat sources in the world ocean, waters that fill the deep ocean can only return to the sea surface as a result of downward mixing of heat from the sea surface to the bottom and vice versa and this occurs through eddy diffusion. Along our presentation, mainly through the analysis of the deepest CTD casts taken from 2009 to 2011 in the eastern basins and in particular in the Ionian Sea, we will show a significant change in the deep thermohaline structure (including its biogeochemical and hydrological characteristics), giving an indication on the time scale of the renewal of deep

  18. A reverse taxonomic approach to assess macrofaunal distribution patterns in abyssal Pacific polymetallic nodule fields.

    PubMed

    Janssen, Annika; Kaiser, Stefanie; Meißner, Karin; Brenke, Nils; Menot, Lenaick; Martínez Arbizu, Pedro

    2015-01-01

    Heightened interest in the exploitation of deep seafloor minerals is raising questions on the consequences for the resident fauna. Assessing species ranges and determination of processes underlying current species distributions are prerequisites to conservation planning and predicting faunal responses to changing environmental conditions. The abyssal central Pacific nodule belt, located between the Clarion and Clipperton Fracture Zones (CCZ), is an area prospected for mining of polymetallic nodules. We examined variations in genetic diversity and broad-scale connectivity of isopods and polychaetes across the CCZ. Faunal assemblages were studied from two mining claims (the eastern German and French license areas) located 1300 km apart and influenced by different productivity regimes. Using a reverse taxonomy approach based on DNA barcoding, we tested to what extent distance and large-scale changes in environmental parameters lead to differentiation in two macrofaunal taxa exhibiting different functions and life-history patterns. A fragment of the mitochondrial gene Cytochrome Oxidase Subunit 1 (COI) was analyzed. At a 97% threshold the molecular operational taxonomic units (MOTUs) corresponded well to morphological species. Molecular analyses indicated high local and regional diversity mostly because of large numbers of singletons in the samples. Consequently, variation in composition of genotypic clusters between sites was exceedingly large partly due to paucity of deep-sea sampling and faunal patchiness. A higher proportion of wide-ranging species in polychaetes was contrasted with mostly restricted distributions in isopods. Remarkably, several cryptic lineages appeared to be sympatric and occurred in taxa with putatively good dispersal abilities, whereas some brooding lineages revealed broad distributions across the CCZ. Geographic distance could explain variation in faunal connectivity between regions and sites to some extent, while assumed dispersal

  19. An abyssal carbonate compensation depth overshoot in the aftermath of the Palaeocene-Eocene Thermal Maximum

    NASA Astrophysics Data System (ADS)

    Penman, Donald E.; Turner, Sandra Kirtland; Sexton, Philip F.; Norris, Richard D.; Dickson, Alexander J.; Boulila, Slah; Ridgwell, Andy; Zeebe, Richard E.; Zachos, James C.; Cameron, Adele; Westerhold, Thomas; Röhl, Ursula

    2016-08-01

    During the Palaeocene-Eocene Thermal Maximum (PETM) about 56 million years ago, thousands of petagrams of carbon were released into the atmosphere and ocean in just a few thousand years, followed by gradual sequestration over approximately 200,000 years. If silicate weathering is one of the key negative feedbacks that removed this carbon, a period of seawater calcium carbonate saturation greater than pre-event levels would be expected during the event's recovery phase. In marine sediments, this should be recorded as a temporary deepening of the depth below which no calcite is preserved -- the calcite compensation depth (CCD). Previous and new sedimentary records from sites that were above the pre-PETM CCD show enhanced carbonate accumulation following the PETM. A new record from an abyssal site in the North Atlantic that lay below the pre-PETM CCD shows a period of carbonate preservation beginning about 70,000 years after the onset of the PETM, providing the first direct evidence for an over-deepening of the CCD. This record confirms an overshoot in ocean carbonate saturation during the PETM recovery. Simulations with two earth system models support scenarios for the PETM that involve a large initial carbon release followed by prolonged low-level emissions, consistent with the timing of CCD deepening in our record. Our findings indicate that sequestration of these carbon emissions was most likely the result of both globally enhanced calcite burial above the CCD and, at least in the North Atlantic, an over-deepening of the CCD.

  20. A Reverse Taxonomic Approach to Assess Macrofaunal Distribution Patterns in Abyssal Pacific Polymetallic Nodule Fields

    PubMed Central

    Janssen, Annika; Kaiser, Stefanie; Meißner, Karin; Brenke, Nils; Menot, Lenaick; Martínez Arbizu, Pedro

    2015-01-01

    Heightened interest in the exploitation of deep seafloor minerals is raising questions on the consequences for the resident fauna. Assessing species ranges and determination of processes underlying current species distributions are prerequisites to conservation planning and predicting faunal responses to changing environmental conditions. The abyssal central Pacific nodule belt, located between the Clarion and Clipperton Fracture Zones (CCZ), is an area prospected for mining of polymetallic nodules. We examined variations in genetic diversity and broad-scale connectivity of isopods and polychaetes across the CCZ. Faunal assemblages were studied from two mining claims (the eastern German and French license areas) located 1300 km apart and influenced by different productivity regimes. Using a reverse taxonomy approach based on DNA barcoding, we tested to what extent distance and large-scale changes in environmental parameters lead to differentiation in two macrofaunal taxa exhibiting different functions and life-history patterns. A fragment of the mitochondrial gene Cytochrome Oxidase Subunit 1 (COI) was analyzed. At a 97% threshold the molecular operational taxonomic units (MOTUs) corresponded well to morphological species. Molecular analyses indicated high local and regional diversity mostly because of large numbers of singletons in the samples. Consequently, variation in composition of genotypic clusters between sites was exceedingly large partly due to paucity of deep-sea sampling and faunal patchiness. A higher proportion of wide-ranging species in polychaetes was contrasted with mostly restricted distributions in isopods. Remarkably, several cryptic lineages appeared to be sympatric and occurred in taxa with putatively good dispersal abilities, whereas some brooding lineages revealed broad distributions across the CCZ. Geographic distance could explain variation in faunal connectivity between regions and sites to some extent, while assumed dispersal

  1. Population genetic structure of the abyssal grenadier (Coryphaenoides armatus) around the mid-Atlantic ridge

    NASA Astrophysics Data System (ADS)

    Ritchie, H.; Cousins, N. J.; Cregeen, S. J.; Piertney, S. B.

    2013-12-01

    Understanding the factors that affect the levels and distribution of genetic diversity in oceanic and deep sea environments is a central focus in marine population genetics. Whilst it has been considered that the oceans represent a homogenous environment that would facilitate dispersal and minimise population structure, it is now clear that topographical features and current patterns can influence the extent of spatial gene flow and promote significant population genetic divergence even at local scales. Here we examine patterns of population genetic structure among N. Atlantic populations of the cosmopolitan abyssal grenadier Coryphaenoides armatus in relation to two hypothesised barriers to gene flow-the mid-Atlantic Ridge and the Charlie-Gibbs Fracture Zone/Sub-Polar Front. A suite of microsatellite markers were developed to examine the spatial pattern of allelic variation among 210 individuals from ten sampling locations encompassing sites east and west of the MAR and north and south of the CGFZ, plus a geographically distinct sample of individuals from the Crozet Islands in the Indian Ocean. Considerable genetic diversity was detected among individuals (na=5-13 and HO=0.46-0.69 across populations) but with an overall lack of genetic divergence between populations. Pairwise estimates of divergence among NE Atlantic samples were small and non-significant (max FST=0.04) and Structure-based Bayesian analysis of genetic clusters returned no distinct population structure. The only indication of genetic structure was between the Atlantic and Indian Oceans, with FST estimates of ca. 0.05. Patterns of genetic diversity and divergence are discussed in relation to what has been resolved in Coryphaenoides congeners, and what is known about the life history and ecology of C. armatus.

  2. Moored observation of abyssal flow and temperature near a hydrothermal vent on the Southwest Indian Ridge

    NASA Astrophysics Data System (ADS)

    Liao, Guanghong; Zhou, Beifeng; Liang, Chujin; Zhou, Huaiyang; Ding, Tao; Wang, Yuan; Dong, Changming

    2016-01-01

    Four moorings were deployed near "Dragon Flag," an active hydrothermal vent in the valley of the Southwest Indian Ridge. The goal was to examine the variability of currents and temperature, which will guide the trajectory of spreading plumes. The mean current was cross-isobath, and the circulation was characterized by a submesoscale circulation. Observed currents also showed fluctuations with periods of 1-15 days. The inferred phase speed and wavelength for the wave with a period of 4.4 day are 10.4 km d-1 and 45.8km, respectively, which are consistent with the topographic Rossby wave theory. The persistent warming tendency with corresponding variation of salinity based on background θ-S properties may be caused by background circulation and divergence of the water column. The warming or cooling episodes were most likely as signatures of isopycnal surface depression or uplifting induced by the moving of mesoscale eddies. Well-resolved rotary spectra exhibited important nonlinear interactions between inertial and semidiurnal tide in the velocity and temperature records. Amplification of near-inertial currents in the near bottom is also exposed. These discoveries provided new evidence for the nonlinear interaction and trapped near-inertial waves by the ridge, which occurred in the deep ocean of the Southern Hemisphere. Such nonlinear interaction may represent a significant energy loss pathway for the internal waves, and part of the decay of such motion would likely result in increased mixing to maintain the abyssal stratification. Enhanced near-inertial motions can play a major role for the local advection of hydrothermal plumes.

  3. Organic carbon cycling in abyssal benthic food chains: numerical simulations of bioenhancement by sewage sludge

    NASA Astrophysics Data System (ADS)

    Rowe, Gilbert T.

    1998-05-01

    The hypothetical bioenhancement of the endemic benthic biota on an oligotrophic abyssal plain by organic carbon has been investigated with mathematical simulation experiments. First, the responses of the biomass and respiration to seasonal variations in the rain of organic carbon (POC) have been simulated in a simplified benthic assemblage (sediment organic carbon, sediment-dwelling heterotrophs (bacteria, meiofauna, macrofauna and detritus feeding megafauna) and predatory megafauna), with no added organic matter. These calculations were based on measured standing stocks and respiration in the central North Pacific (5.8 km depth, 31°N Lat.×159°W Long.). The dynamic relationships in this natural "oligotrophic" food chain were then subjected to added inputs of organic carbon presumed to be in sewage sludge. Two examples are presented: a modest but continuous input of organic carbon (100 mg C m -2 d -1) and a year-long pulse of the same intensity. The continuous input forced the biomass and community respiration to steadily increase until they reached steady state in 15 years at values similar to those found on a typical continental shelf. The pulse exhibited the same pattern, but biomass and respiration returned to levels found under natural oligotrophic conditions several years after cessation of intensified carbon loading. The responses of the sediment community to added organic matter were validated using information from a deep-ocean sewage disposal site (DWD106) off the coast of New Jersey. The models are also used to illustrate an approach for estimating possible transfers of potentially toxic contaminants, such as total polycyclic aromatic hydrocarbons (tPAHs), in lipid-rich eggs. In the future it will be necessary to validate model results with deep-ocean in situ experiments.

  4. Links between surface productivity and deep ocean particle flux at the Porcupine Abyssal Plain sustained observatory

    NASA Astrophysics Data System (ADS)

    Frigstad, H.; Henson, S. A.; Hartman, S. E.; Omar, A. M.; Jeansson, E.; Cole, H.; Pebody, C.; Lampitt, R. S.

    2015-10-01

    In this study we present hydrography, biogeochemistry and sediment trap observations between 2003 and 2012 at Porcupine Abyssal Plain (PAP) sustained observatory in the Northeast Atlantic. The time series is valuable as it allows for investigation of the link between surface productivity and deep ocean carbon flux. The region is a perennial sink for CO2, with an average uptake of around 1.5 mmol m-2 day-1. The average monthly drawdowns of inorganic carbon and nitrogen were used to quantify the net community production (NCP) and new production. Seasonal NCP and new production were found to be 4.57 ± 0.85 mol C m-2 and 0.37 ± 0.14 mol N m-2, respectively. The C : N ratio was high (12) compared to the Redfield ratio (6.6), and the production calculated from carbon was higher than production calculated from nitrogen, which is indicative of carbon overconsumption. The export ratio and transfer efficiency were 16 and 4 %, respectively, and the site thereby showed high flux attenuation. Particle tracking was used to examine the source region of material in the sediment trap, and there was large variation in source regions, both between and within years. There were higher correlations between surface productivity and export flux when using the particle-tracking approach, than by comparing with the mean productivity in a 100 km box around the PAP site. However, the differences in correlation coefficients were not significant, and a longer time series is needed to draw conclusions on applying particle tracking in sediment trap analyses.

  5. Activation of Fault Structures South of the La Habra Earthquake Rupture As Evidenced By UAVSAR Imaging

    NASA Astrophysics Data System (ADS)

    Donnellan, A.; Parker, J. W.; Grant Ludwig, L.; Hauksson, E.

    2014-12-01

    The 28 March, 2014 M 5.2 La Habra earthquake occurred on a northeast striking, northwest dipping left-lateral oblique thrust fault at the northeastern margin of the LA Basin, where regional right-lateral shear is accommodated by major northwest trending faults of the Peninsular Ranges, and north-south shortening is accommodated by north-dipping thrust faults and east-west trending folds of the Transverse Ranges. The La Habra mainshock location and focal mechanism is northwest of but sub-parallel to the Puente Hills thrust fault. Relocated seismicity highlights a northeast-trending rupture plane consistent with the magnitude and focal mechanism of the event. NASA's UAVSAR L-Band radar instrument was flown for north and south looking lines before the earthquake on 22 January 2014. The north looking line was reflown three days after the earthquake on 31 March, 2014, and the south looking line was reflown a week later on 4 April 2014. The UAVSAR Repeat Pass Interferogram (RPI) products show deformation consistent with the location of the mainshock beneath the town of La Habra. The results also show considerable aseismic northward horizontal deformation with minor uplift in the West Coyote Hills, south of the relocated seismicity. Inversion of the combined interferograms is consistent with south dipping low-angle (7°) shallow slip that corresponds to bedding plane attitudes and a mapped unconformity. The entire West Coyote Hills show 37 mm of modeled northward slip with an additional 34 mm of modeled slip concentrated near the Coyote Hills Park northeast of the intersection of Rosecrans Avenue and North Gilbert Street. A narrow band of shortening was also observed with UAVSAR, and confirmed with on-the-ground field observations, at the Trojan Way Kink Band, nearly one fault dimension southwest of the main rupture.

  6. Inter-annual species-level variations in an abyssal polychaete assemblage (Sta. M, NE Pacific, 4000 m)

    NASA Astrophysics Data System (ADS)

    Laguionie-Marchais, Claire; Paterson, Gordon L. J.; Bett, Brian J.; Smith, Kenneth L.; Ruhl, Henry A.

    2016-01-01

    Understanding the dynamics of abyssal community structure and function has become increasingly important as deep-sea resource exploitation and climate change pressures are expected to ramp up. This time-series study investigates macrofaunal polychaete dynamics at a station in the North East Pacific (Sta. M; 35° N 123° W, 4000 m, 1991-2011). Infaunal polychaete species were identified and their proxy biomass and proxy energy use rate estimated. The assemblage comprised 167 species, having a composition consistent with other abyssal areas globally. Significant changes in univariate and multivariate parameters (rank abundance distribution, Simpson's diversity index, and species and functional group composition) were detected across 1991-2011. However, no change in biomass or energy use rate was apparent through the time-series. The largest changes in the polychaete assemblage coincided with both an increase in sinking particulate organic carbon flux to the seafloor in 2007, and a 40 km relocation of the sampling location to a site 100 m shallower, preventing a conclusive assessment of which might drive the observed variation. Analyses prior to the change of sampling location showed that the polychaete assemblage composition dynamics were primary driven by food supply variation. Changes in several species were also lagged to changes in POC flux by 4-10 months. The polychaete fauna exhibited a significant positive relationship between total density and total energy use rate, suggesting population-level tracking of a common resource (e.g. POC flux food supply). Neither compensatory nor energetic zero-sum dynamics were detected among the polychaete assemblage, but the results suggest that the latter occur in the macrofaunal community as a whole. The results do indicate (a) potential control of species composition, and the density of individual key species, by food supply, when the time-series prior to the sampling location was analysed separately, and (b) generally

  7. Epifaunal and shallow infaunal foraminiferal communities at three abyssal NE Atlantic sites subject to differing phytodetritus input regimes

    NASA Astrophysics Data System (ADS)

    Gooday, Andrew J.

    1996-09-01

    Multiple corer samples (0-1 cm sediment layer and overlying phytodetritus) obtained at three northeast Atlantic sites were analysed for Rose Bengal stained benthic foraminifera ( > 63 μm). Strong phytodetrital pulses have been documented at the northern site on the Porcupine Abyssal Plain (PAP; 48°50'N, 16°30'W) but not at the southern sites on the Madeira Abyssal Plain (MAP; 31°N, 20°W) and Cape Verde Abyssal Plain (CVAP; 21°N, 31°W). Foraminiferal densities reflected surface primary productivity estimates fairly closely, being higher at the PAP (mean: 800 per 25.5 cm 2 sample area= 314 per 10 cm z) than at the southern sites (mean: 502 per sample =197 per 10 cm Z). In part, this difference was attributable to the presence of a substantial phytodetrital deposit in two of the PAP samples. The phytodetrital aggregates provided organically-enriched microenvironments exploited by dense foraminiferal populations, which accounted for up to 22.4% of the entire foraminiferal fauna. They were of low diversity with a few dominant species (notably the rotaliid Epistominella exigua), a population structure typical of organically enriched systems. Most of the phytodetrital species were much less common in the sediments. The total (i.e. sediment + phytodetritus) populations were highly diverse (123-167 species); but southern site populations were somewhat more diverse than PAP populations, and the two PAP phytodetritus-rich cores had higher dominance values than other samples. Total species assemblages were broadly similar. However, in addition to the phytodetritus-dwelling species, some species of Reophax, Leptohalysis, Lagenammina and "Hyperammina" were more abundant at the PAP site, perhaps benefiting from degraded phytodetritus or from the associated bacterial populations. A few species, e.g. Subreophax aduncus and Lagenammina tubulata, were more abundant at the southern sites.

  8. Normal faults, normal friction?

    NASA Astrophysics Data System (ADS)

    Collettini, Cristiano; Sibson, Richard H.

    2001-10-01

    Debate continues as to whether normal faults may be seismically active at very low dips (δ < 30°) in the upper continental crust. An updated compilation of dip estimates (n = 25) has been prepared from focal mechanisms of shallow, intracontinental, normal-slip earthquakes (M > 5.5; slip vector raking 90° ± 30° in the fault plane) where the rupture plane is unambiguously discriminated. The dip distribution for these moderate-to-large normal fault ruptures extends from 65° > δ > 30°, corresponding to a range, 25° < θr < 60°, for the reactivation angle between the fault and inferred vertical σ1. In a comparable data set previously obtained for reverse fault ruptures (n = 33), the active dip distribution is 10° < δ = θr < 60°. For vertical and horizontal σ1 trajectories within extensional and compressional tectonic regimes, respectively, dip-slip reactivation is thus restricted to faults oriented at θr ≤ 60° to inferred σ1. Apparent lockup at θr ≈ 60° in each dip distribution and a dominant 30° ± 5° peak in the reverse fault dip distribution, are both consistent with a friction coefficient μs ≈ 0.6, toward the bottom of Byerlee's experimental range, though localized fluid overpressuring may be needed for reactivation of less favorably oriented faults.

  9. Three-dimensional potential flow over hills and oval mounds

    NASA Technical Reports Server (NTRS)

    Siegel, R.

    1976-01-01

    An analysis was made of the potential flow behavior for an initially uniform flow passing over a single axisymmetric hill, an oval mound, and a combination of two hills. Small perturbation theory was used, and the resulting Laplace equation for the perturbation velocity potential was solved by using either a product solution or a Green's function. The three dimensional solution is of interest in calculating the pressure distribution around obstacles, the flow of pollutants carried by the wind, and the augmentation of wind velocity for windmill siting. The augmentation in velocity at the top of a hill was found to be proportional to the hill height relative to a characteristic width dimension of the hill. An axisymmetric hill produced about 20 percent less velocity increase than a two dimensional ridge having the same cross-sectional profile.

  10. Growth, reproduction and possible recruitment variability in the abyssal brittle star Ophiocten hastatum (Ophiuroidea: Echinodermata) in the NE Atlantic

    NASA Astrophysics Data System (ADS)

    Gage, John D.; Anderson, Roslyn M.; Tyler, Paul A.; Chapman, Rachel; Dolan, Emily

    2004-06-01

    Growth was studied from skeletal growth markers in the cosmopolitan abyssal brittle star Ophiocten hastatm. Samples for analysis were taken at five sites located in the southern (2900 m) and central (2000 m) Rockall Trough, at ca. 3000 and 4000 m in the Porcupine Seabight, and at 4850 m on the Porcupine Abyssal Plain. Growth bands were assumed to reflect an annual cycle in skeletal growth. Band measurements on arm vertebrae, standardised to disc diameter, were used to provide size-at-age data and size-increment data that took into account overgrowth of early bands in older individuals. The Richards growth function marginally provides best fit to pooled size-at-age data, although the asymptote-less Tanaka function and the Gompertz growth function also provided good fit to size-at-age data which showed a rather linear growth pattern with little indication of a growth asymptote. Log e transformed size-increment data were linearised by applying the Ford-Walford method to approximate Gompertz growth so that growth could be compared at the five sites. Grouped linear regression and analysis of covariance showed no significant differences between growth at the sites and a common fitted regression. However, pairwise comparisons suggest growth differences with increasing bathymetric separation. Oocyte size frequencies measured from histological preparations of the gonad of specimens from the Porcupine Abyssal Plain indicate marked reproductive periodicity, with spawn-out in late winter that is likely followed by planktotrophic early development in spring with benthic settlement in summer. Although usually rare in the trawl and epibenthic sled samples, several years of successful recruitment followed by a period when recruitment was low or absent might explain size structure observed in a single unusually large sample from the Rockall Trough. This is consistent with previous observations during the late 1990s of a large population increase on the Porcupine Abyssal Plain

  11. Character, paleoenvironment, rate of accumulation, and evidence for seismic triggering of Holocene turbidites, Canada Abyssal Plain, Arctic Ocean

    USGS Publications Warehouse

    Grantz, A.; Phillips, R.L.; Mullen, M.W.; Starratt, S.W.; Jones, Glenn A.; Naidu, A.S.; Finney, B.P.

    1996-01-01

    Four box cores and one piston core show that Holocene sedimentation on the southern Canada Abyssal Plain for the last 8010??120 yr has consisted of a continuing rain of pelagic organic and ice-rafted elastic sediment with a net accumulation rate during the late Holocene of ???10 mm/1000 yr, and episodically emplaced turbidites 1-5 m thick deposited at intervals of 830 to 3450 yr (average 2000 yr). The average net accumulation rate of the mixed sequence of turbidites and thin pelagite interbeds in the cores is about 1.2 m/1000 yr. Physiography suggests that the turbidites originated on the Mackenzie Delta or its clinoform, and ??13C values of -27 to - 25??? in the turbidites are compatible with a provenance on a delta. Extant displaced neritic and lower slope to basin plain calcareous benthic foraminifers coexist in the turbidite units. Their joint occurence indicates that the turbidites originated on the modern continental shelf and entrained sediment from the slope and rise enroute to their final resting place on the Canada Abyssal Plain. The presence of Middle Pleistocene diatoms in the turbidites suggests, in addition, that the turbidites may have originated in shallow submarine slides beneath the upper slope or outer shelf. Small but consistent differences in organic carbon content and ??13C values between the turbidite units suggest that they did not share an identical provenance, which is at least compatible with an origin in slope failures. The primary provenance of the ice-rafted component of the pelagic beds was the glaciated terrane of northwestern Canada; and the provenance of the turbidite units was Pleistocene and Holocene sedimentary deposits on the outer continental shelf and upper slope of the Mackenzie Delta. Largely local derivation of the sediment of the Canada Abyssal Plain indicates that sediment accumulation rates in the Arctic Ocean are valid only for regions with similar depositional sources and processes, and that these rates cannot be

  12. Solar system fault detection

    DOEpatents

    Farrington, R.B.; Pruett, J.C. Jr.

    1984-05-14

    A fault detecting apparatus and method are provided for use with an active solar system. The apparatus provides an indication as to whether one or more predetermined faults have occurred in the solar system. The apparatus includes a plurality of sensors, each sensor being used in determining whether a predetermined condition is present. The outputs of the sensors are combined in a pre-established manner in accordance with the kind of predetermined faults to be detected. Indicators communicate with the outputs generated by combining the sensor outputs to give the user of the solar system and the apparatus an indication as to whether a predetermined fault has occurred. Upon detection and indication of any predetermined fault, the user can take appropriate corrective action so that the overall reliability and efficiency of the active solar system are increased.

  13. Solar system fault detection

    DOEpatents

    Farrington, Robert B.; Pruett, Jr., James C.

    1986-01-01

    A fault detecting apparatus and method are provided for use with an active solar system. The apparatus provides an indication as to whether one or more predetermined faults have occurred in the solar system. The apparatus includes a plurality of sensors, each sensor being used in determining whether a predetermined condition is present. The outputs of the sensors are combined in a pre-established manner in accordance with the kind of predetermined faults to be detected. Indicators communicate with the outputs generated by combining the sensor outputs to give the user of the solar system and the apparatus an indication as to whether a predetermined fault has occurred. Upon detection and indication of any predetermined fault, the user can take appropriate corrective action so that the overall reliability and efficiency of the active solar system are increased.

  14. PLANS AND SECTIONS. WEIR SPILLWAY. TEXAS HILL CANAL STA. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PLANS AND SECTIONS. WEIR SPILLWAY. TEXAS HILL CANAL - STA. 132+82.15. TEXAS HILL CANAL AND DISTRIBUTION SYSTEM. United States Department of Interior, Bureau of Reclamation; Gila Project, Arizona, Wellton-Mohawk Division. Drawing No. 50-D-3200, dated February 7, 1955, Denver, Colorado - Wellton-Mohawk Irrigation System, Relift Station, Texas Hill Canal 2.5, Northern Terminus of Avenue 51 East, approximately .5 mile south of Union Pacific Railroad, Wellton, Yuma County, AZ

  15. Dynamics of binary asteroids. I - Hill's case

    NASA Astrophysics Data System (ADS)

    Chauvineau, B.; Mignard, F.

    1990-02-01

    The present investigation of the dynamics of hypothesized binary (or multiple) asteroids attempts to evaluate the likelihood of their dynamic stability, giving attention to the trajectories of Hill's (1977) problem (including only the gravitational perturbation of the sun) to define the effects of solar perturbations on the relative motion of a binary asteroid. Only for the cases of close binary asteroids, can the Jacobian constant be unambiguously related to the semimajor axis of a weakly disturbed Keplerian ellipse. A greater likelihood is found for a stable asteroid with retrograde orbit, in both the synodic and the inertial frames, that with direct orbit.

  16. Earth and space scientists Visit Capitol Hill

    NASA Astrophysics Data System (ADS)

    O'Riordan, Catherine

    AGU's Office of Public Affairs organizes frequent opportunities for members to meet with Congress. Recently AGU members participated in two events: an annual Congressional Visits Day and the Coalition for National Science Funding congressional reception.Over 200 scientists and engineers met with key legislators and their staffs on Capitol Hill in Washington, D.C. as part of the 10th annual Science, Engineering, and Technology Congressional Visits Day (CVD) held on 10-11 May. In their meetings, participants advocated this year's CVD theme: Federally funded research secures our nation's future.

  17. How clays weaken faults.

    NASA Astrophysics Data System (ADS)

    van der Pluijm, Ben A.; Schleicher, Anja M.; Warr, Laurence N.

    2010-05-01

    The weakness of upper crustal faults has been variably attributed to (i) low values of normal stress, (ii) elevated pore-fluid pressure, and (iii) low frictional strength. Direct observations on natural faults rocks provide new evidence for the role of frictional properties on fault strength, as illustrated by our recent work on samples from the San Andreas Fault Observatory at Depth (SAFOD) drillhole at Parkfield, California. Mudrock samples from fault zones at ~3066 m and ~3296 m measured depth show variably spaced and interconnected networks of displacement surfaces that consist of host rock particles that are abundantly coated by polished films with occasional striations. Transmission electron microscopy and X-ray diffraction study of the surfaces reveal the occurrence of neocrystallized thin-film clay coatings containing illite-smectite (I-S) and chlorite-smectite (C-S) phases. X-ray texture goniometry shows that the crystallographic fabric of these faults rocks is characteristically low, in spite of an abundance of clay phases. 40Ar/39Ar dating of the illitic mix-layered coatings demonstrate recent crystallization and reveal the initiation of an "older" fault strand (~8 Ma) at 3066 m measured depth, and a "younger" fault strand (~4 Ma) at 3296 m measured depth. Today, the younger strand is the site of active creep behavior, reflecting continued activation of these clay-weakened zones. We propose that the majority of slow fault creep is controlled by the high density of thin (< 100nm thick) nano-coatings on fracture surfaces, which become sufficiently smectite-rich and interconnected at low angles to allow slip with minimal breakage of stronger matrix clasts. Displacements are accommodated by localized frictional slip along coated particle surfaces and hydrated smectitic phases, in combination with intracrystalline deformation of the clay lattice, associated with extensive mineral dissolution, mass transfer and continued growth of expandable layers. The

  18. The Kunlun Fault

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Kunlun fault is one of the gigantic strike-slip faults that bound the north side of Tibet. Left-lateral motion along the 1,500-kilometer (932-mile) length of the Kunlun has occurred uniformly for the last 40,000 years at a rate of 1.1 centimeter per year, creating a cumulative offset of more than 400 meters. In this image, two splays of the fault are clearly seen crossing from east to west. The northern fault juxtaposes sedimentary rocks of the mountains against alluvial fans. Its trace is also marked by lines of vegetation, which appear red in the image. The southern, younger fault cuts through the alluvium. A dark linear area in the center of the image is wet ground where groundwater has ponded against the fault. Measurements from the image of displacements of young streams that cross the fault show 15 to 75 meters (16 to 82 yards) of left-lateral offset. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) acquired the visible light and near infrared scene on July 20, 2000. Image courtesy NASA/GSFC/MITI/ERSDAC/JAROS, and the U.S./Japan ASTER Science Team

  19. Fault detection and isolation

    NASA Technical Reports Server (NTRS)

    Bernath, Greg

    1994-01-01

    In order for a current satellite-based navigation system (such as the Global Positioning System, GPS) to meet integrity requirements, there must be a way of detecting erroneous measurements, without help from outside the system. This process is called Fault Detection and Isolation (FDI). Fault detection requires at least one redundant measurement, and can be done with a parity space algorithm. The best way around the fault isolation problem is not necessarily isolating the bad measurement, but finding a new combination of measurements which excludes it.

  20. Structure and Origin of the Columbia Hills, Gusev Crater, Mars

    NASA Astrophysics Data System (ADS)

    McCoy, Timothy; Sims, M.; Crumpler, L. S.; Cohen, B. A.; Blaney, D. L.; Schmidt, M. E.; Treguier, E.; d'Uston, C.; Rice, J. W.; Tornabene, L. L.; Squyres, S. W.; Arvidson, R. E.; Haldemann, A.

    2007-10-01

    The Mars Exploration Rover Spirit has yielded profound insights into features at millimeter to decimeter scales. However, the origin of the Columbia Hills has remained enigmatic given the traverse across one peak [1]. We present a geologic history of the Hills consistent with their morphology, bedding attitudes, and stratigraphy. The Columbia Hills form a triangle 4.2 by 2.3 km, are bounded by linear to slightly concave margins, lie near the center of Gusev Crater, and have peaks rising to 90 m. Bedding dips away from a NNE-SSW axis cutting the Tennessee Valley. Husband Hill dips (15-32°) are steeper than local topography ( 8-10°) and those on West Spur are conformable with greater scatter in strike and shallower dips (7-15°). Husband Hill is cored by volcaniclastic rocks and impact breccias altered to various extents (Wishstone, Watchtower and Descartes classes), ringed by ultramafic volcaniclastic rocks and sulfate-cemented sands (Algonquin and Peace classes), ringed by localized impact breccias and volcaniclastic deposits (West Spur and Home Plate) [2]. The Columbia Hills likely formed by (1) Uplift of the Gusev Crater central peak, raising the Hills to 3 km above the crater floor, assuming the Hills are deeply-rooted and subsequently buried. Uplift by overlapping crater rims is inconsistent with bedding attitudes, but may have modified the margins of the Hills. (2) Draping by impact and volcaniclastic rocks and sands with localized alteration and cementation. Fragile rocks (Peace) and in situ soils (Paso Robles) would not have survived Gusev Crater formation. (3) Mass wasting of the Tennessee Valley removed tens of meters from the peak of the Hills, exposing older units in the core, (4) Plains (Adirondack) basalts surrounded and embayed the Hills, and (5) Small impacts redistributed rocks. [1] Rice J.W. (2004) Fall AGU, #P23B-03. [2] Squyres S.W. et al. (2006) JGR 111, E02S11.

  1. Hill crossing during preheating after hilltop inflation

    NASA Astrophysics Data System (ADS)

    Antusch, Stefan; Nolde, David; Orani, Stefano

    2015-06-01

    In ``hilltop inflation'', inflation takes place when the inflaton field slowly rolls from close to a maximum of its potential (i.e. the ``hilltop'') towards its minimum. When the inflaton potential is associated with a phase transition, possible topological defects produced during this phase transition, such as domain walls, are efficiently diluted during inflation. It is typically assumed that they also do not reform after inflation, i.e. that the inflaton field stays on its side of the ``hill'', finally performing damped oscillations around the minimum of the potential. In this paper we study the linear and the non-linear phases of preheating after hilltop inflation. We find that the fluctuations of the inflaton field during the tachyonic oscillation phase grow strong enough to allow the inflaton field to form regions in position space where it crosses ``over the top of the hill'' towards the ``wrong vacuum''. We investigate the formation and behaviour of these overshooting regions using lattice simulations: rather than durable domain walls, these regions form oscillon-like structures (i.e. localized bubbles that oscillate between the two vacua) which should be included in a careful study of preheating in hilltop inflation.

  2. New type of hill-top inflation

    NASA Astrophysics Data System (ADS)

    Barvinsky, A. O.; Kamenshchik, A. Yu.; Nesterov, D. V.

    2016-01-01

    We suggest a new type of hill-top inflation originating from the initial conditions in the form of the microcanonical density matrix for the cosmological model with a large number of quantum fields conformally coupled to gravity. Initial conditions for inflation are set up by cosmological instantons describing underbarrier oscillations in the vicinity of the inflaton potential maximum. These periodic oscillations of the inflaton field and cosmological scale factor are obtained within the approximation of two coupled oscillators subject to the slow roll regime in the Euclidean time. This regime is characterized by rapid oscillations of the scale factor on the background of a slowly varying inflaton, which guarantees smallness of slow roll parameters epsilon and η of the following inflation stage. A hill-like shape of the inflaton potential is shown to be generated by logarithmic loop corrections to the tree-level asymptotically shift-invariant potential in the non-minimal Higgs inflation model and R2-gravity. The solution to the problem of hierarchy between the Planckian scale and the inflation scale is discussed within the concept of conformal higher spin fields, which also suggests the mechanism bringing the model below the gravitational cutoff and, thus, protecting it from large graviton loop corrections.

  3. Spirit's Express Route to 'Columbia Hills'

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This map illustrates the Mars Exploration Rover Spirit's position as of sol 112 (April 26, 2004), near the crater called 'Missoula.' Like a train on a tight schedule, Spirit will make regular stops along the way to its ultimate destination, the 'Columbia Hills.' At each stop, or 'station,' the rover will briefly analyze the area's rocks and soils. Each tick mark on the rover's route represents one sol's worth of travel, or about 60 to 70 meters (200 to 230 feet). Rover planners estimate that Spirit will reach the hills around mid-June. Presently, the rover is stopped at a site called 'Plains Station.'

    The color thermal data show how well different surface features hold onto heat. Red indicates a higher thermal inertia associated with rocky terrain (cooler in the day, warmer at night); blue indicates a lower thermal inertia associated with smaller particles and fewer rocks (warmer at night, cooler in the day). During its traverse, Spirit will document the causes of these thermal variations.

    The map comprises data from the camera on NASA's Mars Global Surveyor orbiter and the thermal emission imaging system on NASA's Mars Odyssey orbiter.

  4. Spirit's Express Route to 'Columbia Hills'

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This map illustrates the Mars Exploration Rover Spirit's position as of sol 112 (April 26, 2004), near the crater called 'Missoula.' Like a train on a tight schedule, Spirit will make regular stops along the way to its ultimate destination, the 'Columbia Hills.' At each stop, or 'station,' the rover will briefly analyze the area's rocks and soils. Each tick mark on the rover's route represents one sol's worth of travel, or about 60 to 70 meters (200 to 230 feet). Rover planners estimate that Spirit will reach the hills around mid-June. Presently, the rover is stopped at a site called 'Plains Station.'

    The color thermal data show how well different surface features hold onto heat. Red indicates warmth; blue indicates coolness. Areas with higher temperatures are more likely to be rocky, as rocks absorb heat. Lower temperatures denote small particles and fewer rocks. During its traverse, Spirit will document the causes of these temperature variations.

    The map comprises data from the camera on NASA's Mars Global Surveyor orbiter and the thermal emission imaging system on NASA's Mars Odyssey orbiter.

  5. Morphological and ontogenetic stratification of abyssal and hadal Eurythenes gryllus sensu lato (Amphipoda: Lysianassoidea) from the Peru-Chile Trench

    NASA Astrophysics Data System (ADS)

    Eustace, Ryan M.; Ritchie, Heather; Kilgallen, Niamh M.; Piertney, Stuart B.; Jamieson, Alan J.

    2016-03-01

    The globally ubiquitous lysianassoid amphipod, Eurythenes gryllus, has been shown to consist of multiple genetically distinct cryptic taxa, with depth considered a major driver of speciation and morphological divergence. Here we examine morphological variation of E. gryllus sensu lato through a continuous depth distribution that spans from abyssal (3000-6000 m) into hadal depths (>6000 m) in the Peru-Chile Trench (SE Pacific Ocean). Three distinct morphospecies were identified: one was confirmed as being E. magellanicus (4602-5329 m) based on DNA sequence and morphological similarity. The other two morphologically distinct species were named based upon depth of occurrence; Abyssal (4602-6173 m) and Hadal (6173-8074 m). The three Eurythenes morphospecies showed vertical ontogenetic stratification across their bathymetric range, where juveniles were found shallower in their depth range and mature females deeper. Potential ecological and evolutionary drivers that explain the observed patterns of intra and inter-specific structure, such as hydrostatic pressure and topographical isolation, are discussed.

  6. Temporal and depth-related differences in prokaryotic communities in abyssal sediments associated with particulate organic carbon flux

    NASA Astrophysics Data System (ADS)

    Moeseneder, M. M.; Smith, K. L.; Ruhl, H. A.; Jones, D. O. B.; Witte, U.; Prosser, J. I.

    2012-12-01

    Particulate organic carbon (POC) flux is hypothesized to be the most important parameter influencing activity and biomass of prokaryotic and faunal communities in the abyssal seafloor, but there is little evidence of POC-related changes in community composition of prokaryotes. This hypothesis was tested by 16S rRNA-gene-based analysis of prokaryotic DNA and RNA extracted from abyssal seafloor sediments during periods of low and high POC flux. Fingerprint analysis of prokaryotic communities indicated that approximately 50% of the phylotypes were identical at each sediment horizon, regardless of the temporal variations in POC flux. However, phylotypes were also detected that represented a relatively dynamic component of these communities and were probably strongly influenced by the prevalent POC flux regime. These patterns were also detected in deeper sediment horizons. DNA- and RNA-based community profiles differed, although both approaches had similar community dynamics. Crenarchaeota showed the strongest shift in community composition in response to availability of labile POC, indicating that POC flux may have a more pronounced impact on crenarchaeal communities than on bacterial communities. The high number of phylotypes common to each sample time suggests that both standing stock and active prokaryotic communities are stable.

  7. Composition and distribution of bivalves of the abyssal plain adjacent to the Kuril-Kamchatka Trench (Pacific Ocean)

    NASA Astrophysics Data System (ADS)

    Kamenev, Gennady M.

    2015-01-01

    The KuramBio German-Russian deep-sea expedition ("Sonne", 2012) revealed a rich fauna of bivalves (55 species belonging to 21 families) on the abyssal plain (4861-5787 m) adjacent to the Kuril-Kamchatka Trench. Per station species richness varied from 18 to 33 species. The richest families were Cuspidariidae (7 species), Tindariidae (6 species), Thyasiridae (6 species), and Xylophagidae (5 species). The families Nuculidae, Malletidae, Yoldiidae, Mytilidae, Protocuspidariidae, and Verticordiidae were represented by a single species. Representatives of the family Siliculidae were recorded in the northwestern Pacific for the first time. Thirteen species (23.6%) were most common in the investigated northwestern Pacific region. Nine species (16.4%) were only found at one of the stations. Eight species (14.5%) are first records for the northwestern Pacific, of which Yoldiella cf. jeffreysi (Hidalgo, 1877), Pristigloma cf. albaSanders and Allen, 1973, and Syssitomya cf. pourtalesianaOliver, 2012 were previously known only for the Atlantic Ocean. The high diversity and richness of the bivalve fauna on the abyssal plain in the Kuril-Kamchatka Trench area may be connected to the favorable feeding conditions in this, one of the most highly productive areas of the Pacific Ocean.

  8. Measuring fault tolerance with the FTAPE fault injection tool

    NASA Technical Reports Server (NTRS)

    Tsai, Timothy K.; Iyer, Ravishankar K.

    1995-01-01

    This paper describes FTAPE (Fault Tolerance And Performance Evaluator), a tool that can be used to compare fault-tolerant computers. The major parts of the tool include a system-wide fault-injector, a workload generator, and a workload activity measurement tool. The workload creates high stress conditions on the machine. Using stress-based injection, the fault injector is able to utilize knowledge of the workload activity to ensure a high level of fault propagation. The errors/fault ratio, performance degradation, and number of system crashes are presented as measures of fault tolerance.

  9. Measuring fault tolerance with the FTAPE fault injection tool

    NASA Astrophysics Data System (ADS)

    Tsai, Timothy K.; Iyer, Ravishankar K.

    1995-05-01

    This paper describes FTAPE (Fault Tolerance And Performance Evaluator), a tool that can be used to compare fault-tolerant computers. The major parts of the tool include a system-wide fault-injector, a workload generator, and a workload activity measurement tool. The workload creates high stress conditions on the machine. Using stress-based injection, the fault injector is able to utilize knowledge of the workload activity to ensure a high level of fault propagation. The errors/fault ratio, performance degradation, and number of system crashes are presented as measures of fault tolerance.

  10. MODOO: A modular and mobile deep ocean observatory and its application to the Porcupine Abyssal Plain

    NASA Astrophysics Data System (ADS)

    Karstensen, Johannes; Greinert, Jens; Lampitt, Richard; Grant, Fiona; Priede, Monty; Pagnani, Maureen

    2010-05-01

    Many of todays scientific questions require to observe the various processes in the ocean in parallel and from the air/sea interface to the sea-floor interior. Moreover, socioeconomic as well as scientific requirements may even demand to excess data in real time - for example for marine safety or to adapt the instrumentation to episodic environmental conditions. Here we describe a muti-disciplinary deep ocean observatory that has been designed within the European FP6 ESONET Network of Excellence to meet todays scientific and socioeconomic requirements for ocean observatories. MODOO, the Modular and mObile Deep Ocean Observatory, combines underwater acoustic modules with a surface telecommunication module to access and combine a variety of instrumentation from the sea surface to below the sea floor. MODOO's first application will be at the Porcupine Abyssal Plain: here a BOBO deep sea lander will be connected to a full water depth (4800m) deep sea mooring with meteorological package that belongs to the European FP7 EuroSITES network. The main scientific mission of this MODOO configuration is to investigate physical and biogeochemical processes that control the propagation and impact of near surface events (e.g. chlorophyll bloom) to the deep sea. For this mission we make use of physical (T/S recorder, current meters/profilers) and biogeochemical sensors (nitrate, fluorescence, oxygen, turbidity, particle flux/composition) combined with deep sea photography. Scientific guest missions will be seismic records and passive acoustics to detect deep sea marine life. The first MODOO installation is planned to be installed by the end of May 2010 for a three month test. The MODOO instrumentation is not simply mounted together but part of the MODOO concept is to add a common time stamp to the individual instrumentations data set. All instrumentation that is directly connected to the acoustic modems - for the PAP application this will be T/S/turbidity, ADCP, seismometer, oxygen

  11. Character and Implications of a Newly Identified Creeping Strand of the San Andreas fault NE of Salton Sea, Southern California

    NASA Astrophysics Data System (ADS)

    Janecke, S. U.; Markowski, D.

    2015-12-01

    The overdue earthquake on the Coachella section, San Andreas fault (SAF), the model ShakeOut earthquake, and the conflict between cross-fault models involving the Extra fault array and mapped shortening in the Durmid Hill area motivate new analyses at the southern SAF tip. Geologic mapping, LiDAR, seismic reflection, magnetic and gravity datasets, and aerial photography confirm the existence of the East Shoreline strand (ESS) of the SAF southwest of the main trace of the SAF. We mapped the 15 km long ESS, in a band northeast side of the Salton Sea. Other data suggest that the ESS continues N to the latitude of the Mecca Hills, and is >35 km long. The ESS cuts and folds upper Holocene beds and appears to creep, based on discovery of large NW-striking cracks in modern beach deposits. The two traces of the SAF are parallel and ~0.5 to ~2.5 km apart. Groups of east, SE, and ENE-striking strike-slip cross-faults connect the master dextral faults of the SAF. There are few sinistral-normal faults that could be part of the Extra fault array. The 1-km wide ESS contains short, discontinuous traces of NW-striking dextral-oblique faults. These en-echelon faults bound steeply dipping Pleistocene beds, cut out section, parallel tight NW-trending folds, and produced growth folds. Beds commonly dip toward the ESS on both sides, in accord with persistent NE-SW shortening across the ESS. The dispersed fault-fold structural style of the ESS is due to decollements in faulted mud-rich Pliocene to Holocene sediment and ramps and flats along the strike-slip faults. A sheared ladder-like geometric model of the two master dextral strands of the SAF and their intervening cross-faults, best explains the field relationships and geophysical datasets. Contraction across >40 km2 of the southernmost SAF zone in the Durmid Hills suggest that interaction of active structures in the SAF zone may inhibit the nucleation of large earthquakes in this region. The ESS may cross the northern Coachella

  12. Magnetic Fabric Associated with Faulting of Poorly Consolidated Basin Sediments of the Rio Grande Rift, New Mexico, USA

    NASA Astrophysics Data System (ADS)

    Hudson, M. R.; Minor, S. A.; Caine, J. S.

    2015-12-01

    Permanent strain in sediments associated with shallow fault zones can be difficult to characterize. Anisotropy of magnetic susceptibility (AMS) data were obtained from 120 samples at 6 sites to assess the nature of fault-related AMS fabrics for 4 faults cutting Miocene-Pliocene basin fill sediments of the Rio Grande rift of north-central New Mexico. The San Ysidro (3 sites), Sand Hill, and West Paradise faults within the northern Albuquerque basin have normal offset whereas an unnamed fault near Buckman in the western Española basin has oblique strike-slip offset. Previous studies have shown that detrital magnetite controls magnetic susceptibility in rift sandstones, and in a 50-m-long hanging wall traverse of the San Ysidro fault, non-gouge samples have typical sedimentary AMS fabrics with Kmax and Kint axes (defining magnetic foliation) scattered within bedding. For the 5 normal-fault sites, samples from fault cores or adjacent mixed zones that lie within 1 m of the principal slip surface developed common deformation fabrics with (1) magnetic foliation inclined in the same azimuth but more shallowly dipping than the fault plane, and (2) magnetic lineation plunging down foliation dip with nearly the same trend as the fault striae, although nearer for sand versus clay gouge samples. These relations suggest that the sampled fault materials deformed by particulate flow with alignment of magnetite grains in the plane of maximum shortening. For a 2-m-long traverse at the Buckman site, horizontal sedimentary AMS foliation persists to < 15 cm to the fault slip surface, wherein foliation in sand and clay gouge rotates toward the steeply dipping fault plane in a sense consistent with sinistral offset. Collectively these data suggest permanent deformation fabrics were localized within < 1 m of fault surfaces and that AMS fabrics from gouge samples can provide kinematic information for faults in unconsolidated sediments which may lack associated slickenlines.

  13. Geophysical Investigations Along the Hayward Fault, Northern California, and Their Implications on Earthquake Hazards

    NASA Astrophysics Data System (ADS)

    Ponce, D. A.; Graymer, R. W.; Hildenbrand, T. G.; Jachens, R. C.; Simpson, R. W.

    2007-12-01

    Geophysical studies indicate that the Hayward Fault follows a pre-existing basement structure and that local geologic features play an important role in earthquake seismicity. The recent creeping trace of the Hayward Fault extends for about 90 km from San Pablo Bay in the northwest to Fremont in the southeast, and together with its northern extension, the Rodgers Creek Fault, is regarded as one of the most hazardous faults in northern California. The Hayward Fault is predominantly a right-lateral strike-slip fault that forms the western boundary of the East Bay Hills and separates Franciscan Complex rocks on the southwest from Coast Range Ophiolite and Great Valley Sequence basement rocks on the northeast. The Hayward Fault is characterized by distinct linear gravity and magnetic anomalies that correlate with changes in geology, structural trends, creep rates, and clusters of seismicity. These correlations indicate the existence of fault-zone discontinuities that probably reflect changes in mechanical properties. These fault-zone discontinuities may play a role in defining fault segments--locations where recurring seismic ruptures may tend to nucleate or terminate. Along the central part of the Hayward Fault, a prominent gravity and magnetic anomaly correlates with an exposed gabbro body, the San Leandro gabbro. Modeling of these anomalies reveals that the San Leandro gabbro is much more extensive in the subsurface than the outcrop pattern suggests, extending to a depth of about 6-8 km. The inferred extent of the San Leandro gabbro, it's geologic setting, and associated seismicity suggest that the Hayward Fault evolved from a pre-existing basement feature, similar to the ancestral Coast Range Fault. Combined modeling and relocated double-difference seismicity data indicate that the dip of the fault surface varies from near vertical in the north to about 75 degrees in the central part to about 50 degrees in the south near Fremont and ultimately connects with the

  14. Influence of Transcontinental arch on Cretaceous listric-normal faulting, west flank, Denver basin

    SciTech Connect

    Davis, T.L.

    1983-08-01

    Seismic studies along the west flank of the Denver basin near Boulder and Greeley, Colorado illustrate the interrelationship between shallow listric-normal faulting in the Cretaceous and deeper basement-controlled faulting. Deeper fault systems, primarily associated with the Transcontinental arch, control the styles and causative mechanisms of listric-normal faulting that developed in the Cretaceous. Three major stratigraphic levels of listric-normal faulting occur in the Boulder-Greeley area. These tectonic sensitive intervals are present in the following Cretaceous formations: Laramie-Fox Hills-upper Pierre, middle Pierre Hygiene zone, and the Niobrara-Carlile-Greenhorn. Documentation of the listric-normal fault style reveals a Wattenberg high, a horst block or positive feature of the greater Transcontinental arch, was active in the east Boulder-Greeley area during Cretaceous time. Paleotectonic events associated with the Wattenberg high are traced through analysis of the listric-normal fault systems that occur in the area. These styles are important to recognize because of their stratigraphic and structural influence on Cretaceous petroleum reservoir systems in the Denver basin. Similar styles of listric-normal faulting occur in the Cretaceous in many Rocky Mountain foreland basins.

  15. OpenStudio - Fault Modeling

    2014-09-19

    This software record documents the OpenStudio fault model development portion of the Fault Detection and Diagnostics LDRD project.The software provides a suite of OpenStudio measures (scripts) for modeling typical HVAC system faults in commercial buildings and also included supporting materials: example projects and OpenStudio measures for reporting fault costs and energy impacts.

  16. OVERVIEW OF GOLD HILL MILL, ROAD, AND WHITE PINE TALC ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    OVERVIEW OF GOLD HILL MILL, ROAD, AND WHITE PINE TALC MINE LOOKING EAST. THE OPENING TO THE TALC MINE IS IN THE DARK AREA AT CENTER LEFT EDGE. WARM SPRINGS CAMP IS OUT OF FRAME TO THE RIGHT. - Gold Hill Mill, Warm Spring Canyon Road, Death Valley Junction, Inyo County, CA

  17. STREAMLINES IN STRATIFIED FLOW OVER A THREE-DIMENSIONAL HILL

    EPA Science Inventory

    A fluid modeling study was performed in the EPA Fluid Modeling Facility's stratified towing tank to determine the effects of stratification on the flow field over a three-dimensional hill. Streamlines in the stratified flow over an axisymmetric hill were marked with a dye tracer ...

  18. VIEW LOOKING WEST TOWARD RESERVOIR HILL. THE SPRR HOTEL WAS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW LOOKING WEST TOWARD RESERVOIR HILL. THE SPRR HOTEL WAS LOCATED IN THE STRIPED AREA AT THE BOTTOM OF THE IMAGE, AND THE TRACK RAN BETWEEN THE HILL AND THE HOTEL. - Southern Pacific Railroad Water Settling Reservoir, Yuma Crossing, south bank of Colorado River at foot of Madison Avenue, Yuma, Yuma County, AZ

  19. 78 FR 76100 - Black Hills National Forest Advisory Board

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-16

    ...; ] DEPARTMENT OF AGRICULTURE Forest Service Black Hills National Forest Advisory Board AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Black Hills National Forest Advisory Board (Board) will... Committee Act of 1972 (5 U.S.C. App. II), the Forest and Rangeland Renewable Resources Planning Act of...

  20. 78 FR 73187 - Black Hills National Forest Advisory Board

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-05

    ... Forest Service Black Hills National Forest Advisory Board AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Black Hills National Forest Advisory Board (Board) will meet in Rapid City, South.... II), the Forest and Rangeland Renewable Resources Planning Act of 1974 (16 U.S.C. 1600 et.seq.),...

  1. 77 FR 75120 - Black Hills National Forest Advisory Board

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-19

    ... Forest Service Black Hills National Forest Advisory Board AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Black Hills National Forest Advisory Board will meet in Rapid City, South Dakota...) (FACA); and the Forest and Rangeland Renewable Resources Planning Act of 1974 (16 U.S.C. 1600...

  2. View of south boundary of Easter Hill project site for ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of south boundary of Easter Hill project site for right of way for Hoffman Boulevard. Buildings No. 11 and 14 at right in trees. Looking west - Easter Hill Village, Bordered by South Twenty-sixth Street, South Twenty-eighth Street, Hinkley Avenue, Foothill Avenue & Corto Square, Richmond, Contra Costa County, CA

  3. VIEW TO SOUTHEAST TOWARD QUARTERMASTER BUILDINGS GROUP AND RESERVOIR HILL, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW TO SOUTHEAST TOWARD QUARTERMASTER BUILDINGS GROUP AND RESERVOIR HILL, FROM AMMUNITION (IGLOO) HILL. (Part 2 of a 3 view panorama; see also CA-2398-J-1 and CA-2398-16.) - Hamilton Field, East of Nave Drive, Novato, Marin County, CA

  4. AmeriFlux US-Blk Black Hills

    SciTech Connect

    Meyers, Tilden

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site US-Blk Black Hills. Site Description - The Black Hills tower was established by the Institute for Atmospheric Studies of the South Dakota School of Mines and Technology.

  5. View of sports field and Easter Hill at west side ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of sports field and Easter Hill at west side of project site. Looking southwest - Easter Hill Village, Bordered by South Twenty-sixth Street, South Twenty-eighth Street, Hinkley Avenue, Foothill Avenue & Corto Square, Richmond, Contra Costa County, CA

  6. View of sports field and Easter Hill at west side ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of sports field and Easter Hill at west side of project site. Looking west - Easter Hill Village, Bordered by South Twenty-sixth Street, South Twenty-eighth Street, Hinkley Avenue, Foothill Avenue & Corto Square, Richmond, Contra Costa County, CA

  7. View of sports field from Easter Hill looking at intersection ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of sports field from Easter Hill looking at intersection of South Twenty-Sixth Street and Foothill Avenue at left center rear. Buildings No. 36, 35, 25, 27, and 29, from left to right. Looking northeast - Easter Hill Village, Bordered by South Twenty-sixth Street, South Twenty-eighth Street, Hinkley Avenue, Foothill Avenue & Corto Square, Richmond, Contra Costa County, CA

  8. Spectral parameter power series representation for Hill's discriminant

    SciTech Connect

    Khmelnytskaya, K.V.; Rosu, H.C.

    2010-11-15

    We establish a series representation of the Hill discriminant based on the spectral parameter power series (SPPS) recently introduced by Kravchenko. We also show the invariance of the Hill discriminant under a Darboux transformation and employing the Mathieu case the feasibility of this type of series for numerical calculations of the eigenspectrum.

  9. 27 CFR 9.162 - Sta. Rita Hills.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Sta. Rita Hills. 9.162.... Rita Hills. (a) Name. The name of the viticultural area described in this section is “Sta. Rita Hills”. For purposes of part 4 of this chapter, “Sta. Rita Hills” is a term of viticultural significance....

  10. 27 CFR 9.162 - Sta. Rita Hills.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Sta. Rita Hills. 9.162.... Rita Hills. (a) Name. The name of the viticultural area described in this section is “Sta. Rita Hills”. For purposes of part 4 of this chapter, “Sta. Rita Hills” is a term of viticultural significance....

  11. 27 CFR 9.162 - Sta. Rita Hills.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Sta. Rita Hills. 9.162.... Rita Hills. (a) Name. The name of the viticultural area described in this section is “Sta. Rita Hills”. For purposes of part 4 of this chapter, “Sta. Rita Hills” is a term of viticultural significance....

  12. 27 CFR 9.162 - Sta. Rita Hills.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Sta. Rita Hills. 9.162.... Rita Hills. (a) Name. The name of the viticultural area described in this section is “Sta. Rita Hills”. For purposes of part 4 of this chapter, “Sta. Rita Hills” is a term of viticultural significance....

  13. 27 CFR 9.162 - Sta. Rita Hills.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Sta. Rita Hills. 9.162.... Rita Hills. (a) Name. The name of the viticultural area described in this section is “Sta. Rita Hills”. For purposes of part 4 of this chapter, “Sta. Rita Hills” is a term of viticultural significance....

  14. 83. GENERAL VIEW FROM NORTH END OF GUN HILL PLATFORM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    83. GENERAL VIEW FROM NORTH END OF GUN HILL PLATFORM OF 3RD AVENUE EL SHOWING THE SOUTHBOUND TRACK APPROACH INTO GUN HILL STATION. 7TH AVENUE EXPRESS EL ABOVE. - Interborough Rapid Transit Company, Third Avenue Elevated Line, Borough of the Bronx, New York County, NY

  15. Accounting for imperfect detection in Hill numbers for biodiversity studies

    USGS Publications Warehouse

    Broms, Kristin M.; Hooten, Mevin B.; Fitzpatrick, Ryan M.

    2015-01-01

    The occupancy-based Hill number estimators are always at their asymptotic values (i.e. as if an infinite number of samples have been taken for the study region), therefore making it easy to compare biodiversity between different assemblages. In addition, the Hill numbers are computed as derived quantities within a Bayesian hierarchical model, allowing for straightforward inference.

  16. 27 CFR 9.188 - Horse Heaven Hills.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Horse Heaven Hills. 9.188... Horse Heaven Hills. (a) Name. The name of the viticultural area described in this section is “Horse Heaven Hills”. For purposes of part 4 of this chapter, “Horse Heaven Hills” and “Horse Heaven” are...

  17. 27 CFR 9.188 - Horse Heaven Hills.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Horse Heaven Hills. 9.188... Horse Heaven Hills. (a) Name. The name of the viticultural area described in this section is “Horse Heaven Hills”. For purposes of part 4 of this chapter, “Horse Heaven Hills” and “Horse Heaven” are...

  18. 27 CFR 9.188 - Horse Heaven Hills.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Horse Heaven Hills. 9.188... Horse Heaven Hills. (a) Name. The name of the viticultural area described in this section is “Horse Heaven Hills”. For purposes of part 4 of this chapter, “Horse Heaven Hills” and “Horse Heaven” are...

  19. 27 CFR 9.188 - Horse Heaven Hills.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Horse Heaven Hills. 9.188... Horse Heaven Hills. (a) Name. The name of the viticultural area described in this section is “Horse Heaven Hills”. For purposes of part 4 of this chapter, “Horse Heaven Hills” and “Horse Heaven” are...

  20. "This Delightfull Garden": "Rabbit Hill" and the Pastoral Tradition.

    ERIC Educational Resources Information Center

    Jordan, Anne Devereaux

    1997-01-01

    Contends that Robert Lawson's children's book "Rabbit Hill" (1944) falls within the genre of pastoral literature, in the tradition of Edmund Spenser's "Faerie Queen." Examines the history of the genre and finds reasons for classifying Lawson's book as pastoral. Cites classic elements in "Rabbit Hill." Gives five questions for stimulating student…

  1. 3. BUNKER HILL LEAD SMELTER. VIEW IS FROM CIA TO ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. BUNKER HILL LEAD SMELTER. VIEW IS FROM CIA TO THE SOUTHWEST. BUILDINGS NOTED IN ID-29-2 APPEAR, IN ADDITION TO DRY ORE PLANT AND BONNOT COAL PULVERIZING EQUIPMENT BUILDING ON THE RIGHT. - Bunker Hill Lead Smelter, Bradley Rail Siding, Kellogg, Shoshone County, ID

  2. 1. BUNKER HILL LEAD SMELTER. VIEW IS FROM CENTRAL IMPOUNDMENT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. BUNKER HILL LEAD SMELTER. VIEW IS FROM CENTRAL IMPOUNDMENT AREA LOOKING SOUTH. PLANT DRY IS IN CENTER FOREGROUND, SLAG FUMING PLANT IS IN RIGHT FOREGROUND, AND BAG HOUSE IS IN RIGHT BACKGROUND. VARIOUS PLANT STACKS ARE ALSO VISIBLE. - Bunker Hill Lead Smelter, Bradley Rail Siding, Kellogg, Shoshone County, ID

  3. 2. BUNKER HILL LEAD SMELTER. VIEW IS FROM CIA TO ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. BUNKER HILL LEAD SMELTER. VIEW IS FROM CIA TO THE SOUTH. IN FOREGROUND, PLANT DRY, SLAG FUMING PLANT, BLAST FURNACE, SMELTER OFFICE, LEAD AND SILVER REFINERIES ARE VISIBLE, L. TO R. HIGH VELOCITY FLUE LEADS FROM LOWER PLANT TO BAG HOUSE AND STACKS AT TOP OF SMELTING FACILITY. - Bunker Hill Lead Smelter, Bradley Rail Siding, Kellogg, Shoshone County, ID

  4. Hayward Fault, California Interferogram

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This image of California's Hayward fault is an interferogram created using a pair of images taken by Synthetic Aperture Radar(SAR) combined to measure changes in the surface that may have occurred between the time the two images were taken.

    The images were collected by the European Space Agency's Remote Sensing satellites ERS-1 and ERS-2 in June 1992 and September 1997 over the central San Francisco Bay in California.

    The radar image data are shown as a gray-scale image, with the interferometric measurements that show the changes rendered in color. Only the urbanized area could be mapped with these data. The color changes from orange tones to blue tones across the Hayward fault (marked by a thin red line) show about 2-3centimeters (0.8-1.1 inches) of gradual displacement or movement of the southwest side of the fault. The block west of the fault moved horizontally toward the northwest during the 63 months between the acquisition of the two SAR images. This fault movement is called a seismic creep because the fault moved slowly without generating an earthquake.

    Scientists are using the SAR interferometry along with other data collected on the ground to monitor this fault motion in an attempt to estimate the probability of earthquake on the Hayward fault, which last had a major earthquake of magnitude 7 in 1868. This analysis indicates that the northern part of the Hayward fault is creeping all the way from the surface to a depth of 12 kilometers (7.5 miles). This suggests that the potential for a large earthquake on the northern Hayward fault might be less than previously thought. The blue area to the west (lower left) of the fault near the center of the image seemed to move upward relative to the yellow and orange areas nearby by about 2 centimeters (0.8 inches). The cause of this apparent motion is not yet confirmed, but the rise of groundwater levels during the time between the images may have caused the reversal of a small portion of the subsidence that

  5. Cable-fault locator

    NASA Technical Reports Server (NTRS)

    Cason, R. L.; Mcstay, J. J.; Heymann, A. P., Sr.

    1979-01-01

    Inexpensive system automatically indicates location of short-circuited section of power cable. Monitor does not require that cable be disconnected from its power source or that test signals be applied. Instead, ground-current sensors are installed in manholes or at other selected locations along cable run. When fault occurs, sensors transmit information about fault location to control center. Repair crew can be sent to location and cable can be returned to service with minimum of downtime.

  6. Fault rupture segmentation

    NASA Astrophysics Data System (ADS)

    Cleveland, Kenneth Michael

    A critical foundation to earthquake study and hazard assessment is the understanding of controls on fault rupture, including segmentation. Key challenges to understanding fault rupture segmentation include, but are not limited to: What determines if a fault segment will rupture in a single great event or multiple moderate events? How is slip along a fault partitioned between seismic and seismic components? How does the seismicity of a fault segment evolve over time? How representative are past events for assessing future seismic hazards? In order to address the difficult questions regarding fault rupture segmentation, new methods must be developed that utilize the information available. Much of the research presented in this study focuses on the development of new methods for attacking the challenges of understanding fault rupture segmentation. Not only do these methods exploit a broader band of information within the waveform than has traditionally been used, but they also lend themselves to the inclusion of even more seismic phases providing deeper understandings. Additionally, these methods are designed to be fast and efficient with large datasets, allowing them to utilize the enormous volume of data available. Key findings from this body of work include demonstration that focus on fundamental earthquake properties on regional scales can provide general understanding of fault rupture segmentation. We present a more modern, waveform-based method that locates events using cross-correlation of the Rayleigh waves. Additionally, cross-correlation values can also be used to calculate precise earthquake magnitudes. Finally, insight regarding earthquake rupture directivity can be easily and quickly exploited using cross-correlation of surface waves.

  7. Fault lubrication during earthquakes.

    PubMed

    Di Toro, G; Han, R; Hirose, T; De Paola, N; Nielsen, S; Mizoguchi, K; Ferri, F; Cocco, M; Shimamoto, T

    2011-03-24

    The determination of rock friction at seismic slip rates (about 1 m s(-1)) is of paramount importance in earthquake mechanics, as fault friction controls the stress drop, the mechanical work and the frictional heat generated during slip. Given the difficulty in determining friction by seismological methods, elucidating constraints are derived from experimental studies. Here we review a large set of published and unpublished experiments (∼300) performed in rotary shear apparatus at slip rates of 0.1-2.6 m s(-1). The experiments indicate a significant decrease in friction (of up to one order of magnitude), which we term fault lubrication, both for cohesive (silicate-built, quartz-built and carbonate-built) rocks and non-cohesive rocks (clay-rich, anhydrite, gypsum and dolomite gouges) typical of crustal seismogenic sources. The available mechanical work and the associated temperature rise in the slipping zone trigger a number of physicochemical processes (gelification, decarbonation and dehydration reactions, melting and so on) whose products are responsible for fault lubrication. The similarity between (1) experimental and natural fault products and (2) mechanical work measures resulting from these laboratory experiments and seismological estimates suggests that it is reasonable to extrapolate experimental data to conditions typical of earthquake nucleation depths (7-15 km). It seems that faults are lubricated during earthquakes, irrespective of the fault rock composition and of the specific weakening mechanism involved. PMID:21430777

  8. Seeing mountains in mole hills: geographical-slant perception

    NASA Technical Reports Server (NTRS)

    Proffitt, D. R.; Creem, S. H.; Zosh, W. D.; Kaiser, M. K. (Principal Investigator)

    2001-01-01

    When observers face directly toward the incline of a hill, their awareness of the slant of the hill is greatly overestimated, but motoric estimates are much more accurate. The present study examined whether similar results would be found when observers were allowed to view the side of a hill. Observers viewed the cross-sections of hills in real (Experiment 1) and virtual (Experiment 2) environments and estimated the inclines with verbal estimates, by adjusting the cross-section of a disk, and by adjusting a board with their unseen hand to match the inclines. We found that the results for cross-section viewing replicated those found when observers directly face the incline. Even though the angles of hills are directly evident when viewed from the side, slant perceptions are still grossly overestimated.

  9. Decay of isolated hills and saddles on Si(001)

    NASA Astrophysics Data System (ADS)

    Kirschbaum, Pierre; Brendel, Lothar; Roos, Kelly R.; Horn-von Hoegen, Michael; Heringdorf, Frank-J. Meyer zu

    2016-08-01

    We discuss the high temperature decay of isolated hills and saddle points on Si(001). Using in situ dark-field imaging in low energy electron microscopy, we track the movement of individual steps during high temperature annealing. We find different temperature dependent decay rates for the top of the hill compared to a saddle point with low step density that is present in the vicinity of the hill. The decay rate of the hill is always higher than the decay rate at the saddle. The two rates converge with increasing temperature and become equal at temperatures above 1060 °C. We also report an alternating fast and low decay rate for the layer-by-layer decay of the hills. This surprising finding is independent of temperature and is explained by macroscopic strain in the sample.

  10. Seeing mountains in mole hills: geographical-slant perception.

    PubMed

    Proffitt, D R; Creem, S H; Zosh, W D

    2001-09-01

    When observers face directly toward the incline of a hill, their awareness of the slant of the hill is greatly overestimated, but motoric estimates are much more accurate. The present study examined whether similar results would be found when observers were allowed to view the side of a hill. Observers viewed the cross-sections of hills in real (Experiment 1) and virtual (Experiment 2) environments and estimated the inclines with verbal estimates, by adjusting the cross-section of a disk, and by adjusting a board with their unseen hand to match the inclines. We found that the results for cross-section viewing replicated those found when observers directly face the incline. Even though the angles of hills are directly evident when viewed from the side, slant perceptions are still grossly overestimated. PMID:11554677

  11. Comparisons of calculated and measured helicopter noise near instrument hill

    NASA Technical Reports Server (NTRS)

    Bass, Henry E.; You, Chulsoo

    1993-01-01

    The polar parabolic equation (POPE) method solves for the diffraction of sound by a curved surface including a realistic sound speed profile. POPE is outlined briefly to describe diffraction which propagates the field over a hill. Experimental data are compared with POPE predictions using the measured sound speed profile and ground impedance. Two trial cases are considered for the comparisons: the helicopter located at the base of the hill and far away from the base of the hill, respectively. The physical mechanisms for sound propagation over a hill are examined with and of POPE calculations and experimental data. The shedding of rays from the hillside gives an interference effect with a wave along the flat surface beyond the base of a hill.

  12. “First” abyssal record of Stenosemus exaratus (G.O. Sars, 1878) (Mollusca, Polyplacophora) in the North-Atlantic Ocean

    PubMed Central

    Allcock, Louise; Schwabe, Enrico

    2013-01-01

    Abstract The first proven abyssal record of Stenosemus exaratus (G.O. Sars, 1878) is presented on the basis of an ROV study in the Irish Sea. For the first time in situ images of the species and data on the environmental parameters are provided. PMID:23794838

  13. "First" abyssal record of Stenosemus exaratus (G.O. Sars, 1878) (Mollusca, Polyplacophora) in the North-Atlantic Ocean.

    PubMed

    Allcock, Louise; Schwabe, Enrico

    2013-01-01

    The first proven abyssal record of Stenosemus exaratus (G.O. Sars, 1878) is presented on the basis of an ROV study in the Irish Sea. For the first time in situ images of the species and data on the environmental parameters are provided. PMID:23794838

  14. Beacon Hill end moraine, Boston: new explanation of an important urban feature

    USGS Publications Warehouse

    Kaye, Clifford A.

    1976-01-01

    The usefulness of geology to engineers is in direct proportion to how well it helps us predict the subsurface; these predictions, in turn, depend on our knowledge of the geomorphic processes that molded the terrain. The uncertainties of interpretation are particularly great in glaciated terrain because our understanding of both glacial processes and history is so incomplete, a fact well illustrated in Beacon Hill. Recent construction activities in the eastern part of the hill, until now classified as a drumlin, have shown that it is better interpreted as an end moraine formed by a Wisconsonian glacial readvance. Instead of the firm till that was anticipated as foundation material, excavations exposed a complex of sand, gravel, and clay, with only minor zones of till. The structure of these deposits strongly suggests that originally they were plates of the glacial bed that froze to the glacier and were transported englacially. Thrust faulting and other deformations are glacial structures formed within the ice in the glacier's terminal zone. In spite of the complex englacial history, these deposits lost little of their original appearance and intergranular relationships. Upon deglaciation, the frozen moraine thawed, and slumping formed complex secondary structures on the ridge's lower flanks.

  15. Seismicity Characterization and Monitoring at WESTCARB's Proposed Montezuma Hills Geologic Sequestration Site

    SciTech Connect

    Daley, T.M.; Haught, R.; Peterson, J.E.; Boyle, K.; Beyer, J.H.; Hutchings, L.R.

    2010-09-15

    The West Coast Regional Carbon Sequestration Partnership (WESTCARB), in collaboration with Shell Oil Co. performed site characterization for a potential small-scale pilot test of geologic sequestration of carbon dioxide (CO2). The site area, know as Montezuma Hills, is near the town of Rio Vista in northern California. During the process of injection at a CO2 storage site, there is a potential for seismic events due to slippage upon pre-existing discontinuities or due to creation of new fractures. Observations from many injection projects have shown that the energy from these events can be used for monitoring of processes in the reservoir. Typically, the events are of relatively high frequency and very low amplitude. However, there are also well documented (non-CO2-related) cases in which subsurface injection operations have resulted in ground motion felt by near-by communities. Because of the active tectonics in California (in particular the San Andreas Fault system), and the potential for public concern, WESTCARB developed and followed an induced seismicity protocol (Myer and Daley, 2010). This protocol called for assessing the natural seismicity in the area and deploying a monitoring array if necessary. In this report, we present the results of the natural seismicity assessment and the results of an initial temporary deployment of two seismometers at the Montezuma Hills site. Following the temporary array deployment, the project was suspended and the array removed in August of 2010.

  16. Variations in normal faulting and plate deformation along the Mariana trench

    NASA Astrophysics Data System (ADS)

    Zhou, Z.; Lin, J.

    2015-12-01

    We investigate variations in normal faulting along the Mariana trench through analyzing deformation of the subducting Pacific plate and geodynamic modeling. Detailed investigation was focused on three areas where high-resolution multibeam bathymetry data are available: the Southern (S) region at 140.8-144°E; the Central (C) region at 14.7-16.8°N; and the Northern (N) region at 18-21.2°N. In each of the study regions, we analyzed seafloor normal faults and calculated the statistics of fault parameters including strike, throw, density, and location relative to the trench axis. Our analysis revealed several key constraints: (1) Most of the normal faults are sub-parallel to the local strike of the trench axis, indicating that the normal faults were initiated by bending stresses in the subducting plate and not by pre-existing seafloor abyssal tectonic fabrics. (2) The normal faults were likely initiated within the outer rise region and reached maximum throw toward the trench. (3) The S-region has the largest trench relief (average of ~6 km) as well as the largest fault throw (maximum throw reached ~320 m when averaged over 5 km of trench-perpendicular profiles). In contrast, the N-region has much smaller trench relief (~2 km) and smaller fault throw (maximum fault throw reached only ~180 m). We then modeled the subducting plate as an elasto-plastic slab subjected to tectonic forcing at the trench axis, including vertical load (V0), bending moment (M0), and horizontal tensional force (F0). Using the above observations as constraints, modeling revealed the following key results: (1) The best-fitting solutions for the S-region are V0 = 5.8 x 1012 N/m, M0 = 9.6 x 1016 N, and F0 = 3.6 x 1012 N/m, yielding the horizontal extensional force to vertical loading ratio F0/V0 = 62%. (2) The best-fitting V0 for the N- and C-regions are about 33% and 41% that of the S-region. Meanwhile, the best-fitting M0 for the N- and C-regions are about 80% and 60% that of the S-region. (3

  17. Faulting Parameters of the January 16, 1994 Wyomissing Hills, Pennsylvania Earthquakes

    USGS Publications Warehouse

    Ammon, C.J.; Herrmann, Robert B.; Langston, C.A.; Benz, H.

    1998-01-01

    Two events dominated the January 1994, Wyomissing, PA earthquake sequence, an Mw 4.0 foreshock, followed by an Mw 4.6 mainshock. We modeled regional waveforms to estimate the event depth and the moment tensors for the two largest events in the sequence, and examine teleseismic wave-forms recorded on the ARCESS short-period seismic array to estimate the depth and source time function of the mainshock. Our data constrain the depth of the events to be shallower than 5 km, and prefer a depth of 3-5 km. For an assumed depth of 3 km, the mainshock moment tensor is 75% double couple, with (the major double couple) planes striking at 135??N, 347??N, dips of 49??, 46??, and rakes of 68??, 114??. The estimated moment is 8.9 ?? 1022 dyne-cm. The P axis strikes 241??N and plunges 2??, the Tension axis strikes 336??N and plunges 73??. The foreshock inversion results are virtually identical to the mainshock results; for a source depth of three km, we find a major double couple with a strike, dip, and rake of 121??N, 60??, and 66??, respectively. The seismic moment for the foreshock is 1.2 ?? 1022 dyne-cm, which is approximately 13% of the mainshock moment release. These events did not excite high-frequency Lg waves as effectively as typical eastern North American events, and the mainshock had a stress drop in the range of 25-50 bars.

  18. Packaged Fault Model for Geometric Segmentation of Active Faults Into Earthquake Source Faults

    NASA Astrophysics Data System (ADS)

    Nakata, T.; Kumamoto, T.

    2004-12-01

    In Japan, the empirical formula proposed by Matsuda (1975) mainly based on the length of the historical surface fault ruptures and magnitude, is generally applied to estimate the size of future earthquakes from the extent of existing active faults for seismic hazard assessment. Therefore validity of the active fault length and defining individual segment boundaries where propagating ruptures terminate are essential and crucial to the reliability for the accurate assessments. It is, however, not likely for us to clearly identify the behavioral earthquake segments from observation of surface faulting during the historical period, because most of the active faults have longer recurrence intervals than 1000 years in Japan. Besides uncertainties of the datasets obtained mainly from fault trenching studies are quite large for fault grouping/segmentation. This is why new methods or criteria should be applied for active fault grouping/segmentation, and one of the candidates may be geometric criterion of active faults. Matsuda (1990) used _gfive kilometer_h as a critical distance for grouping and separation of neighboring active faults. On the other hand, Nakata and Goto (1998) proposed the geometric criteria such as (1) branching features of active fault traces and (2) characteristic pattern of vertical-slip distribution along the fault traces as tools to predict rupture length of future earthquakes. The branching during the fault rupture propagation is regarded as an effective energy dissipation process and could result in final rupture termination. With respect to the characteristic pattern of vertical-slip distribution, especially with strike-slip components, the up-thrown sides along the faults are, in general, located on the fault blocks in the direction of relative strike-slip. Applying these new geometric criteria to the high-resolution active fault distribution maps, the fault grouping/segmentation could be more practically conducted. We tested this model

  19. Meteoric water in normal fault systems: Oxygen and hydrogen isotopic measurements on authigenic phases in brittle fault rocks

    NASA Astrophysics Data System (ADS)

    Haines, S. H.; Anderson, R.; Mulch, A.; Solum, J. G.; Valley, J. W.; van der Pluijm, B. A.

    2009-12-01

    The nature of fluid circulation systems in normal fault systems is fundamental to understanding the nature of fluid movement within the upper crust, and has important implications for the on-going controversy about the strength of faults. Authigenic phases in clay gouges and fault breccias record the isotopic signature of the fluids they formed in equilibrium with, and can be used to understand the ‘plumbing system’ of brittle fault environments. We obtained paired oxygen and hydrogen isotopic measurements on authigenic illite and/or smectite in clay gouge from normal faults in two geologic environments, 1.) low-angle normal faults (Ruby Mountains detachment, NV; Badwater Turtleback, CA; Panamint range-front detachment; CA; Amargosa detachment; CA; Waterman Hills detachment, CA), and 2.) An intracratonic high-angle normal fault (Moab Fault, UT). All authigenic phases in these clay gouges are moderately light isotopically with respect to oxygen (illite δ18O -2.0 - + 11.5 ‰ SMOW, smectite δ18O +3.6 and 17.9 ‰) and very light isotopically with respect to hydrogen (illite δD -148 to -98 ‰ SMOW, smectite δD -147 to -92 ‰). Fluid compositions calculated from the authigenic clays at temperatures of 50 - 130 ○C (as indicated by clay mineralogy) indicate that both illite and smectite in normal fault clay gouge formed in the presence of near-pristine to moderately-evolved meteoric fluids and that igneous or metamorphic fluids are not involved in clay gouge formation in these normal fault settings. We also obtained paired oxygen and hydrogen isotopic measurements on chlorites derived from footwall chlorite breccias in 4 low-angle normal fault detachment systems (Badwater and Mormon Point Turtlebacks, CA, the Chemehuevi detachment, CA, and the Buckskin-Rawhide detachment, AZ). All chlorites are isotopically light to moderately light with respect to oxygen (δ18O +0.29 to +8.1 ‰ SMOW) and very light with respect to hydrogen (δD -97 to -113 ‰) and indicate

  20. Fault Roughness Records Strength

    NASA Astrophysics Data System (ADS)

    Brodsky, E. E.; Candela, T.; Kirkpatrick, J. D.

    2014-12-01

    Fault roughness is commonly ~0.1-1% at the outcrop exposure scale. More mature faults are smoother than less mature ones, but the overall range of roughness is surprisingly limited which suggests dynamic control. In addition, the power spectra of many exposed fault surfaces follow a single power law over scales from millimeters to 10's of meters. This is another surprising observation as distinct structures such as slickenlines and mullions are clearly visible on the same surfaces at well-defined scales. We can reconcile both observations by suggesting that the roughness of fault surfaces is controlled by the maximum strain that can be supported elastically in the wallrock. If the fault surface topography requires more than 0.1-1% strain, it fails. Invoking wallrock strength explains two additional observations on the Corona Heights fault for which we have extensive roughness data. Firstly, the surface is isotropic below a scale of 30 microns and has grooves at larger scales. Samples from at least three other faults (Dixie Valley, Mount St. Helens and San Andreas) also are isotropic at scales below 10's of microns. If grooves can only persist when the walls of the grooves have a sufficiently low slope to maintain the shape, this scale of isotropy can be predicted based on the measured slip perpendicular roughness data. The observed 30 micron scale at Corona Heights is consistent with an elastic strain of 0.01 estimated from the observed slip perpendicular roughness with a Hurst exponent of 0.8. The second observation at Corona Heights is that slickenlines are not deflected around meter-scale mullions. Yielding of these mullions at centimeter to meter scale is predicted from the slip parallel roughness as measured here. The success of the strain criterion for Corona Heights supports it as the appropriate control on fault roughness. Micromechanically, the criterion implies that failure of the fault surface is a continual process during slip. Macroscopically, the

  1. Fault reactivation control on normal fault growth: an experimental study

    NASA Astrophysics Data System (ADS)

    Bellahsen, Nicolas; Daniel, Jean Marc

    2005-04-01

    Field studies frequently emphasize how fault reactivation is involved in the deformation of the upper crust. However, this phenomenon is generally neglected (except in inversion models) in analogue and numerical models performed to study fault network growth. Using sand/silicon analogue models, we show how pre-existing discontinuities can control the geometry and evolution of a younger fault network. The models show that the reactivation of pre-existing discontinuities and their orientation control: (i) the evolution of the main fault orientation distribution through time, (ii) the geometry of relay fault zones, (iii) the geometry of small scale faulting, and (iv) the geometry and location of fault-controlled basins and depocenters. These results are in good agreement with natural fault networks observed in both the Gulf of Suez and Lake Tanganyika. They demonstrate that heterogeneities such as pre-existing faults should be included in models designed to understand the behavior and the tectonic evolution of sedimentary basins.

  2. Motivations of female Black Hills deer hunters

    USGS Publications Warehouse

    Gigliotti, Larry M.; Covelli Metcalf, Elizabeth

    2016-01-01

    State fish and wildlife agencies are particularly interested in attracting female participation because of the potential to offset declining participation in hunting. Understanding female hunters’ motivations will be critical for designing effective recruitment and retention programs for women hunters. Although female participation in hunting is increasing, males still outnumber females by about tenfold. Gender differences in deer hunters were explored by comparing ratings of eight motivations (social, nature, excitement, meat, challenge, trophy, extra hunting opportunity, and solitude). Hunter types were defined by hunters’ selection of the most important motivation for why they like Black Hills deer hunting. Overall, females and males were relatively similar in their ratings of the eight motivations, and we found 85% gender similarity in the selection of the most important motivation. Women were slightly more motivated by the food aspect of the hunt while men placed slightly more value on the hunt as a sporting activity.

  3. After Conquering 'Husband Hill,' Spirit Moves On

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The first explorer ever to scale a summit on another planet, NASA's Mars Exploration Rover Spirit has begun a long trek downward from the top of 'Husband Hill' to new destinations. As shown in this 180-degree panorama from east of the summit, Spirit's earlier tracks are no longer visible. They are off to the west (to the left in this view). Spirit's next destination is 'Haskin Ridge,' straight ahead along the edge of the steep cliff on the right side of this panorama.

    The scene is a mosaic of images that Spirit took with the navigation camera on the rover's 635th Martian day, or sol, (Oct. 16, 2005) of exploration of Gusev Crater on Mars. This view is presented in a cylindrical projection with geometric seam correction.

  4. Meteorological analysis for Fenton Hill, 1979

    SciTech Connect

    Barr, S.; Wilson, S.K.

    1981-01-01

    Three years of meteorological data have been collected at the Fenton Hill site to establish a local climatic baseline, transport and diffusion climatology, and an initial site for an eventual Valles Caldera meteorological network. Tower-based wind and temperature data at 15 m above ground were supplemented during 1979 with precipitation, humidity and pressure measurements, and a limited program of upper winds. Preliminary analysis of the data has been made to identify major topographic and meteorological driving forces affecting the local climatic variations on diurnal and seasonal time scales. The site is quite high and exposed enough tht external influences such as gradient wind flow and thunderstorms tend to dominate over purely local driving forces in determining climate. Locally generated wind circulations are identifiable at night but tend to be weak and sporadic. The presence of topographic obstacles on the 10- to 100-km scale is observed in the winds.

  5. Seeing sodomy: Fanny Hill's blinding vision.

    PubMed

    Kopelson, K

    1992-01-01

    One of the oddest and most erotic moments in Cleland's Fanny Hill occurs when Fanny is knocked "senseless" by a voyeuristic vision of two young men having anal intercourse. This sodomitical passage demonstrates a dominant culture's strong phobic attraction to a socially peripheral Other against which it defines itself. The passage also represents two types of transgression. On one level, it records an inversion of sex, gender, and class paradigms that structure bourgeois subjectivity. On another level, the passage also transgresses signification itself, exploding as well as inverting those paradigms, in a movement that recalls Barthes's distinction between the coded "studium" of the pornographic and the uncoded "punctum" of the erotic. This transgressive exemption from meaning might well be read, in a Barthesian sense, as true sexual enfranchisement in that, for Barthes, the liberation of sexuality requires the release of sexuality from meaning, and from transgression as meaning. PMID:1431071

  6. AGU climate scientists visit Capitol Hill

    NASA Astrophysics Data System (ADS)

    Hankin, Erik

    2012-02-01

    On 1 February 2012, AGU teamed with 11 other scientific societies to bring 29 scientists researching various aspects of climate change to Washington, D. C., for the second annual Climate Science Day on Capitol Hill. The participants represented a wide range of expertise, from meteorology to agriculture, paleoclimatology to statistics, but all spoke to the reality of climate change as demonstrated in their scientific research. With Congress debating environmental regulations and energy policy amid tight fiscal pressures, it is critical that lawmakers have access to the best climate science to help guide policy decisions. The scientists met with legislators and their staff to discuss the importance of climate science for their districts and the nation and offered their expertise as an ongoing resource to the legislators.

  7. Who's Afraid of the Hill Boundary?

    NASA Astrophysics Data System (ADS)

    Montgomery, Richard

    2014-11-01

    The Jacobi-Maupertuis metric allows one to reformulate Newton's equations as geodesic equations for a Riemannian metric which degenerates at the Hill boundary. We prove that a JM geodesic which comes sufficiently close to a regular point of the boundary contains pairs of conjugate points close to the boundary. We prove the conjugate locus of any point near enough to the boundary is a hypersurface tangent to the boundary. Our method of proof is to reduce analysis of geodesics near the boundary to that of solutions to Newton's equations in the simplest model case: a constant force. This model case is equivalent to the beginning physics problem of throwing balls upward from a fixed point at fixed speeds and describing the resulting arcs, see Fig. 2.

  8. Strain accumulation along the Laguna Salada fault, Baja California, Mexico

    NASA Astrophysics Data System (ADS)

    Savage, J. C.; Lisowski, M.; King, N. E.; Gross, W. K.

    1994-09-01

    Strain accumulation observed over the 1978-1991 interval in a 30 x 100 km aperture trilateration network spanning the Laguna Salada fault is described by the principal strain rates 0.101 +/- 0.012 microstrain/yr N80 deg E +/- 2 deg and -0.021 +/- 0.012 microstrain/yr N 10 deg W +/- 2 deg, extension reckoned coseismic effects of the nearby 1979 Imperial Valley (M = 6.5), 1980 Vistoria (Baja California) (M = 6.4), 1987 Superstition Hills (M = 6.5), and 1987 Elmore Ranch (M = 5.9) earthquakes. The observed strain rates indicate extension at a rate of about 0.08 microstrain/yr perpendicular to the trend (N 35 deg W) of the Salton trough as well as a right-lateral tensor shear strain rate 0.05 microstrain/yr across it. The extension perpendicular to the trough is observed neither farther north near the Salton Sea nor farther south across the Gulf of California. However, Holocene slip on the Laguna Salada fault, about equal parts right-lateral and normal slip, is consistent with the observed strain accumulation. A simple dislocation model intended to explain the observed strain accumulation as a product of slip at depth on the Laguna Salada Fault would require that the fault be listric.

  9. Ash and Steam, Soufriere Hills Volcano, Monserrat

    NASA Technical Reports Server (NTRS)

    2002-01-01

    International Space Station crew members are regularly alerted to dynamic events on the Earth's surface. On request from scientists on the ground, the ISS crew observed and recorded activity from the summit of Soufriere Hills on March 20, 2002. These two images provide a context view of the island (bottom) and a detailed view of the summit plume (top). When the images were taken, the eastern side of the summit region experienced continued lava growth, and reports posted on the Smithsonian Institution's Weekly Volcanic Activity Report indicate that 'large (50-70 m high), fast-growing, spines developed on the dome's summit. These spines periodically collapsed, producing pyroclastic flows down the volcano's east flank that sometimes reached the Tar River fan. Small ash clouds produced from these events reached roughly 1 km above the volcano and drifted westward over Plymouth and Richmond Hill. Ash predominately fell into the sea. Sulfur dioxide emission rates remained high. Theodolite measurements of the dome taken on March 20 yielded a dome height of 1,039 m.' Other photographs by astronauts of Montserrat have been posted on the Earth Observatory: digital photograph number ISS002-E-9309, taken on July 9, 2001; and a recolored and reprojected version of the same image. Digital photograph numbers ISS004-E-8972 and 8973 were taken 20 March, 2002 from Space Station Alpha and were provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

  10. Wheel Tracks from Landing Site to Hills

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Figure 1Figure 2

    Wheel tracks left by the NASA rover Spirit's 3-kilometer (2-mile) trek from its landing site to the 'Columbia Hills' are visible in this orbital view from the Mars Orbiter Camera on NASA's Mars Global Surveyor. Spirit's rover track shows up nicely from orbit because the surfaces disrupted and churned by the wheels are darker than the surrounding, dust-coated plain. North is up.

    The largest crater in the view, dubbed 'Bonneville Crater,' is about 210 meters (230 yards) in diameter. The picture is a composite of Mars Orbiter Camera image R15-02643, taken on March 30, 2004, when Spirit was near the south rim of Bonneville Crater, and image R20-01024, taken Aug. 18, 2004, when Spirit was climbing the hills' western spur, seen in the picture's bottom right corner.

    New Dark Streak Near Spirit In figure 1, frames taken from orbit 20 weeks apart (top pair) and by the NASA rover Spirit at ground level (bottom) show the formation of a new dark streak on the ground in the area where Spirit was driving inside Mars' Gusev Crater in April 2004. The new dark streak and other dark streaks in the area are believed to result from dust devils removing brighter dust from the surface.

    The upper frames were taken by the Mars Orbiter Camera aboard NASA's Mars Global Surveyor. They are from the same pair of images combined to create the orbital view of the NASA rover Spirit's trail from the rover's landing site to the 'Columbia Hills.' The orbiter took the upper-left picture on March 30, 2004 (Spirit's 85th martian day, or sol). It took the upper-right picture on Aug. 18, 2004 (Spirit's sol 223). A dark streak occurs in the larger crater in the lower right quarter of the August image. This streak was not present when the March image was obtained. Inspection of the lower image, which was taken by Spirit's navigation camera when the rover was at

  11. Evidence of synmagmatic foliation in the Selawik Hills, NW Alaska, based on [sup 40]Ar/[sup 39]Ar age determinations

    SciTech Connect

    Solie, D.N. ); Layer, P.W. . Geophysical Inst.)

    1993-04-01

    Based on [sup 40]Ar/[sup 39]Ar plateau ages from various rock units in the Selawik Hills plutonic complex, northwestern Alaska, the units were emplaced in the order syenite/monzonite, followed by nepheline syenite and then quartz monzonite. There is no evidence of disturbance of the Ar isotopic system in the dated plutonic minerals, and the ages compare fairly well with previously published K/Ar data. A cooling history of about ten m.y. for the Selawk Hills rocks is suggested, based on comparison of [sup 40]Ar/[sup 39]Ar ages with apatite fission-track data (Murphy and Till, 1992). Comparison of hornblende plateau ages between nonfoliated and foliated syenite indicates that foliated rocks crystallized later than nonfoliated rocks, but within the initial cooling history of the complex. Foliated syenite/monzonite has mineralogy similar to nonfoliated, but with generally higher color index. Foliated textures are distributed throughout the complex, but are more prevalent to the north, proximal to a large (about 2 km[sup 2]) xenolithic metamorphic block which is bounded on the north by an east-west-trending fault. The authors suggest that synmagmatic fault movement acted as a mechanism causing plutonic foliation and resulting in possible loss of late fluid from semicrystallized syenitic magma to form kspar-rich dikes. Foundering of the xenolithic block within the magma may also have contributed to development of foliation. Continued fault movement is indicated by cataclastic deformation along the fault trace.

  12. Quantifying the role of mitigation hills in reducing tsunami runup

    NASA Astrophysics Data System (ADS)

    Marras, S.; Suckale, J.; Lunghino, B.; Giraldo, F.; Hood, K. M.

    2015-12-01

    Coastal communities around the world are being encouraged to plant or restore vegetation along their shores for the purpose of mitigating tsunami damage. A common setup for these projects is to develop 'mitigation hills' - an ensemble of vegetated hills along the coast - instead of one continuous stretch of vegetation. The rationale behind a staggered-hill setup is to give tree roots more space to grow and deepen. From a fluid-dynamical point of view, however, staggered mitigation hills may have significant drawbacks such as diverting the flow into the low-lying areas of the park, which could entail strong currents in the narrow channels between the hills and lead to erosion of the hills from the sides. The goal of this study is to quantify how mitigation hills affect tsunami runup and to provide constraints on the design of mitigation hills that mitigate tsunami damage using numerical simulations. Our computations of tsunami runup are based on the non-linear shallow water equation solved through a fully implicit, high-order, discontinuous Galerkin method. The adaptive computational grid is fitted to the hill topography to capture geometric effects accurately. A new dynamic subgrid-scale eddy viscosity originally designed for large eddy simulation of compressible flows is used for stabilization and to capture the obstacle-generated turbulence. We have carefully benchmarked our model in 1D and 2D against classical test cases. The included figure shows an example run of tsunami runup through coastal mitigation hills. In the interest of providing generalizable results, we perform a detailed scaling analysis of our model runs. We find that the protective value of mitigation hills depends sensitively on the non-linearity of the incoming wave and the relative height of the wave to the hills. Our simulations also suggest that the assumed initial condition is consequential and we hence consider a range of incoming waves ranging from a simple soliton to a more realistic N

  13. The Abyssal Ocean's Contributions to the Global Energy and Sea Level Budgets Between the 1990s and 2000s

    NASA Astrophysics Data System (ADS)

    Purkey, Sarah Michelle Goldstein

    Over the past three decades, Antarctic Bottom Water (AABW), a cold, dense water-mass produced around Antarctica that feeds the bottom limb of the Meridional Overturning Circulation (MOC), has warmed, freshened, and declined in volume. We quantify water-property changes in the deep Southern Ocean and the abyssal global ocean and evaluate the relative contribution of these abyssal changes to the global energy and sea level rise budgets. We find a strong warming trend throughout the deep (greater than 1000 m) Southern Ocean and abyssal (greater than 4000 m) global oceans, equivalent to a heat flux of 0.095 (+/- 0.062) W m -2 applied over the entire surface area of the Earth, a statistically significant fraction of the present global energy budget. The observed warming pattern is also consistent with a global-scale contraction of AABW, suggesting a slowdown of the bottom limb of the MOC. In addition, freshening of 0.02 PSS-78 per decade is observed in the AABW directly downstream from formation sites along the Antarctic continent, with freshening rates roughly a tenth of this in the deep interior of basins adjacent to Antarctica in the Indian and Pacific sectors of the Southern Ocean. The fresh water flux required to account for the observed freshening of AABW in these two basins is 73 (+/- 26) GT yr -1. Finally, the full-depth steric contributions to SLR calculated along the repeated hydrographic sections are used to assess regional and global rates of SLR owing to mass addition through a full depth SLR budget and compared to mass addition estimated directly using data from the Gravity Recovery And Climate Experiment (GRACE) from 2003--2013. These two independent methods both find a global mean rate of mass addition of 1.5 (+/- 0.4) mm yr -1 over their respective periods with large regional variability with higher rates of mass addition in the North Pacific, South Atlantic, and Indo-Atlantic sector of the Southern Ocean, possibly associated with recent changes in the

  14. Abyssal macrofauna of the Kuril-Kamchatka Trench area (Northwest Pacific) collected by means of a camera-epibenthic sledge

    NASA Astrophysics Data System (ADS)

    Brandt, A.; Elsner, N. O.; Malyutina, M. V.; Brenke, N.; Golovan, O. A.; Lavrenteva, A. V.; Riehl, T.

    2015-01-01

    Abyssal macrofaunal composition of 21 epibenthic sledge hauls from twelve stations taken in the Kuril-Kamchatka Trench (KKT) and at the adjacent abyssal plain, Northwest Pacific, is presented. Sampling with the fine meshed epibenthic sledge yielded higher abundances and species richness than was reported from previous expeditions from board of RV Vityaz. In total 84,651 invertebrates were sampled with RV Sonne between July and September of 2012 (31,854 invertebrates if standardised for 1000 m2 trawled distances) from 41 taxa of different taxonomic ranks (15 phyla, 28 classes, 7 orders) were sampled from a trawled area of 53,708 m² and have been analyzed. Few taxa were frequent and most taxa were rare in the samples, twelve taxa occurred with more than 1% frequency. Of these, the Polychaeta were most abundant followed by the benthic Copepoda and Isopoda. Total numbers of individuals varied between stations and were highest with 4238 individuals at station 2-10 close to the KKT in 4865 m depth and lowest with 374 individuals at station 6-11 in 5305 m depth. At this station also the lowest number of taxa occurred (18 taxa) while the highest number occurred with 31 taxa at station 3-9 in 4991 m depth. Numbers of individuals decreased with increasing depth between 4830 and 5780 m. Crustaceans of the superorder Peracarida were one of the dominating taxa with four orders occurring frequently in most samples. In total, Isopoda were most important and occurred with 59% of all peracarid orders sampled, followed by Amphipoda with 21%, Tanaidacea with 11%, Cumacea with 9%, and Mysidacea with <1%. The communities of the stations (and hauls) of the KKT abyssal area differ in terms of taxon composition from each other. A cluster analysis (nMDS) performed for all sampled stations revealed no clear pattern of community similarity between stations or hauls. All hauls close to the trench (2-9 and 2-10 close to the eastern slope of the KKT; and 3-9 and 4-3 at the western slope) were

  15. Redefining Medlicott-Wadia's main boundary fault from Jhelum to Yamuna: An active fault strand of the main boundary thrust in northwest Himalaya

    NASA Astrophysics Data System (ADS)

    Thakur, V. C.; Jayangondaperumal, R.; Malik, M. A.

    2010-06-01

    The MBT demarcates a tectonic boundary between the Tertiary Sub Himalaya and the pre-Tertiary Lesser Himalaya. South of the MBT, another tectonically important fault extends from Muzaffarabad and Riasi in Jammu-Kashmir to Bilaspur and Nahan in Himachal. Medlicott and Wadia had designated this fault the Main Boundary Fault (MBF) in Simla Hills and Jammu region respectively. In between these two areas, later workers gave local-area names to the MBF as the Riasi Thrust in Jammu, Palampur Thrust in Kangra, Bilaspur Thrust in Simla Hills and Nahan Thrust in Sirmur. We have reviewed and established the tectonostratigraphic framework and physical continuity of the lower Tertiary belt and the MBF. The lower Tertiary belt, lying south of the MBT, has characteristic tectonostratigraphic setting with discontinuous bodies of stromatolite-bearing Proterozoic limestone overlain with depositional contact by the Paleocene-lower part Middle Eocene marine Subathu/Patala formation which in turn overlain by the Upper Oligocene-Lower Miocene non-marine Dharamsala/Murree Formation. To avoid confusion with the MBT, we designate collectively the MBF and related faults as the Medlicott-Wadia Thrust (MWT). The MWT extends east of Hazara-Kashmir syntaxis to river Yamuna, covering a distance of ˜ 700 km. Further east of Yamuna, the lower Tertiary belt pinches out and the MWT merges with the sensuo-stricto MBT. The Proterozoic limestone represents the basement over which the lower Tertiary sediments were deposited. The limestone basement with its cover was detached by the MWT, exhuming to the surface and thrusting over largely the Siwalik group. The reactivated Balakot-Bagh Fault, causative fault for the 2005 Kashmir earthquake, extends southeast with right-step to the Riasi Thrust. The Riasi Thrust shows evidence of reactivation and active tectonic activity in Jammu region. It extends further east to the Palampur Thrust in Kangra reentrant, which lies within the 1905 Kangra earthquake

  16. Characteristics of sinking particles in the upper ocean at the Porcupine Abyssal Plain

    NASA Astrophysics Data System (ADS)

    Riley, Jennifer; Sanders, Richard; Achterberg, Eric

    2010-05-01

    Sinking particles play an important role in the biological carbon pump, transferring carbon from the surface to the deep ocean. Data from deep ocean sediment traps suggest biominerals influence particle settling velocity, by increasing their density. However it is unclear whether this biomineral facilitated sinking applies to the upper ocean and if shape also plays a critical role on the rate at which particles sink. Measurements of particle settling velocity, density and drag were made in order to determine their influences on the particle sinking rate in the upper water column. Samples were taken during a cruise in summer 2009 from the Porcupine Abyssal Plain (PAP site) in the northwest Atlantic. Particles were collected from the base of the mixed layer (approximately 50m) using the Marine Snow Catcher. This instrument samples 100L of water and collects any settling particles in a 5L base chamber over 2 - 3 hours. After settling, the top 95L of water was drained off and any particles collected in the base chamber were transferred to the lab. Particles were individually picked using a Pasteur pipette and subdivided, into categories on the basis of appearance. Settling experiments were conducted in a 2L glass measuring cylinder filled with surface sea water, kept at a constant temperature of 15° C. After each experiment particles were preserved individually in buffered formalin for high quality image analysis back on land. Calculations of both excess density and drag were undertaken using data from microscopic measurements. Five main particle categories were identified; (1) diffuse fluff aggregates, (2) dense fluff aggregates, (3) centred particles (fluff aggregated around a central biomineral test), (4) organisms (biomineralising protists including foraminifera) and (5) calcareous tests. Statistical analysis suggested a significant difference in the rate at which the centred and calcareous particles sank (approximately 248 m day-1 and 1070 m day-1respectively) in

  17. A Geo-traverse at a Passive Continental Margin: the Tagus Abyssal Plain, West Iberia

    NASA Astrophysics Data System (ADS)

    Afilhado, A.; Matias, L.; Mendes-Victor, L.

    2006-12-01

    transitional domain suggests a layered structure for the lithospheric mantle. The location of the main features and trend changes seen on the magnetic anomaly and the Bouguer anomaly maps are compatible to the seismically defined transition to the oceanic domain. Both magnetic and free air profiles modeling are also consistent to a major rock property contrast at this location. Minor features within the oceanic domain indicate some variability of the mass and magnetic dipoles distribution that might be related to different cross cutting of the segment axis and/or non stationary thermo-mechanical conditions of the sea floor spreading process. From 9.4W to the foot of the continental slope, at 10.2W, in a 65km distance, the Bouguer anomaly strongly increases due both to continental crust thinning and Moho shallowing. Magnetic anomalies having peak to peak values of 30 to 90nT and wave length of at least 30km plus the high density blocks modeled at shallow levels, indicate that dense and magnetic rocks should be present at the continental margin. A large body of exhumed continental mantle at the OCT is hardly supported by the data. Even so, the eastern 35km segment of the abyssal plain adjacent to the continental margin is a mass excess segment, bordered by significant magnetic anomalies, in good agreement to an intruded and partly ultramafic lower transitional crust, as suggested by the seismic data.

  18. Scientific contributions of A. V. Hill: exercise physiology pioneer.

    PubMed

    Bassett, David R

    2002-11-01

    Beginning in 1910, A. V. Hill performed careful experiments on the time course of heat production in isolated frog muscle. His research paralleled that of the German biochemist Otto Meyerhof, who measured the changes in muscle glycogen and lactate during contractions and recovery. For their work in discovering the distinction between aerobic and anaerobic metabolism, Hill and Meyerhof were jointly awarded the 1922 Nobel Prize for Physiology or Medicine. Because of Hill's interest in athletics, he sought to apply the concepts discovered in isolated frog muscle to the exercising human. Hill and his colleagues made measurements of O(2) consumption on themselves and other subjects running around an 85-m grass track. In the process of this work, they defined the terms "maximum O(2) intake," "O(2) requirement," and "steady state of exercise." Other contributions of Hill include his discoveries of heat production in nerve, the series elastic component, and the force-velocity equation in muscle. Around the time of World War II, Hill was a leading figure in the Academic Assistance Council, which helped Jewish scientists fleeing Nazi Germany to relocate in the West. He served as a member of the British Parliament from 1940 to 1945 and as a scientific advisor to India. Hill's vision and enthusiasm attracted many scientists to the field of exercise physiology, and he pointed the way toward many of the physiological adaptations that occur with physical training. PMID:12381740

  19. Validated Fault Tolerant Architectures for Space Station

    NASA Technical Reports Server (NTRS)

    Lala, Jaynarayan H.

    1990-01-01

    Viewgraphs on validated fault tolerant architectures for space station are presented. Topics covered include: fault tolerance approach; advanced information processing system (AIPS); and fault tolerant parallel processor (FTPP).

  20. Descent from the Summit of 'Husband Hill' (False Color)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    In late November 2005 while descending 'Husband Hill,' NASA's Mars Exploration Rover Spirit took the most detailed panorama so far of the 'Inner Basin,' the rover's next target destination. Spirit acquired the 405 individual images that make up this 360-degree view of the surrounding terrain using five different filters on the panoramic camera. The rover took the images on Martian days, or sols, 672 to 677 (Nov. 23 to 28, 2005 -- the Thanksgiving holiday weekend).

    This image is a false-color rendering using camera's 750-, 530-, and 430-nanometer filters, emphasizing some colors more than others to enhance striking but subtle color differences among rocks, soils, hills, and plains.

    'Home Plate,' a bright, semi-circular feature scientists hope to investigate, is harder to discern in this image than in earlier views taken from higher up the hill. Spirit acquired this more oblique view, known as the 'Seminole panorama,' from about halfway down the south flank of Husband Hill, 50 meters (164 feet) or so below the summit. Near the center of the panorama, on the horizon, are 'McCool Hill' and 'Ramon Hill,' named, like Husband Hill, in honor of the fallen astronauts of the space shuttle Columbia. Husband Hill is visible behind the rover, on the right and left sides of the panorama. An arc of rover tracks made while avoiding obstacles and getting into position to examine rock outcrops can be traced over a long distance by zooming in to explore the panorama in greater detail.

    Spirit is now significantly farther downhill toward the center of this panorama, en route to Home Plate and other enigmatic soils and outcrop rocks in the quest to uncover the history of Gusev Crater and the 'Columbia Hills.'

  1. Planetary stations and Abyssal Benthic Laboratories: An overview of parallel approaches for long-term investigation in extreme environments

    NASA Technical Reports Server (NTRS)

    Dipippo, S.; Prendin, W.; Gasparoni, F.

    1994-01-01

    In spite of the apparent great differences between deep ocean and space environment, significant similarities can be recognized when considering the possible solutions and technologies enabling the development of remote automatic stations supporting the execution of scientific activities. In this sense it is believed that mutual benefits shall be derived from the exchange of experiences and results between people and organizations involved in research and engineering activities for hostile environments, such as space, deep sea, and polar areas. A significant example of possible technology transfer and common systematic approach is given, which describes in some detail how the solutions and the enabling technologies identified for an Abyssal Benthic Laboratory can be applied for the case of a lunar or planetary station.

  2. Population sizes and growth pressure responses of intestinal microfloras of deep-sea fish retrieved from the abyssal zone.

    PubMed

    Yano, Y; Nakayama, A; Yoshida, K

    1995-12-01

    The intestinal floras of seven deep-sea fish retrieved at depths of from 3,200 to 5,900 m were examined for population sizes and growth responses to pressure. Large populations of culturable bacteria, ranging from 1.1 x 10(sup6) to 3.6 x 10(sup8) cells per ml of contents, were detected when samples were incubated at conditions characteristic of those of the deep sea. Culturable cell counts at in situ pressures were greater than those at atmospheric pressure in all samples. Most of the strains isolated by the spread-plating method at atmospheric pressure later proved barophilic. Barophilic bacteria were the predominant inhabitants of the abyssal fish intestines. PMID:16535199

  3. Geology and geochemistry of samples from Los Alamos National Laboratory HDR Well EE-2, Fenton Hill, New Mexico

    SciTech Connect

    Laney, R.; Laughlin, A.W.; Aldrich, M.J. Jr.

    1981-07-01

    Petrologic, geochemical, and structural analyses of cores and cuttings obtained from 3000 to 4389-m true vertical depth in drill hole EE-2 indicate that this deeper part of the Precambrian section at Fenton Hill, New Mexico is composed primarily of a very heterogeneous and structurally anisotropic metamorphic complex, locally intruded by dikes and sills of granodioritic and monzogranitic composition. In this borehole none of these igneous bodies approach in size the 335-m-thick biotite-granodiorite body encountered at 2591-m depth beneath Fenton Hill in the other two drill holes. Contacts between the igneous and metamorphic rocks range from sharp and discordant to gradational. Analysis of cuttings indicates that clay-rich alteration zones are relatively common in the openhole portion of EE-2. These zones average about 20 m in thickness. Fracture sets in the Precambrian basement rock intersected by the EE-2 well bore mostly trend northeast and are steeply dipping to vertical; however, one of the sets dips gently to the northwest. Slickensided fault planes are present in a core (No.5) taken from a true vertical depth of 4195 m. Available core orientation data and geologic inference suggest that the faults dip steeply and trend between N.42/sup 0/ and 59/sup 0/E.

  4. Gold-silver mining districts, alteration zones, and paleolandforms in the Miocene Bodie Hills Volcanic Field, California and Nevada

    USGS Publications Warehouse

    Vikre, Peter G.; John, David A.; du Bray, Edward A.; Fleck, Robert J.

    2015-01-01

      Based on volcanic stratigraphy, geochronology, remnant paleosurfaces, and paleopotentiometric surfaces in mining districts and alteration zones, present landforms in the Bodie Hills volcanic field reflect incremental construction of stratovolcanoes and large- to small-volume flow-domes, magmatic inflation, and fault displacements. Landform evolution began with construction of the 15–13 Ma Masonic and 13–12 Ma Aurora volcanic centers in the northwestern and northeastern parts of the field, respectively. Smaller volcanoes erupted at ~11–10 Ma in, between, and south of these centers as erosional detritus accumulated north of the field in Fletcher Valley. Distally sourced, 9.7–9.3 Ma Eureka Valley Tuff filled drainages and depressions among older volcanoes and was partly covered by nearly synchronous eruptives during construction of four large 10–8 Ma volcanoes, in the southern part of the field. The lack of significant internal fault displacement, distribution of Eureka Valley Tuff, and elevation estimates derived from floras, suggest that the Bodie Hills volcanic field attained present elevations mostly through volcano construction and magmatic inflation, and that maximum paleoelevations (>8,500 ft) at the end of large volume eruptions at ~8 Ma are similar to present elevations.

  5. Cyclic magnetite dissolution in Pleistocene sediments of the abyssal northwest Pacific Ocean: Evidence for glacial oxygen depletion and carbon trapping

    NASA Astrophysics Data System (ADS)

    Korff, Lucia; Dobeneck, Tilo; Frederichs, Thomas; Kasten, Sabine; Kuhn, Gerhard; Gersonde, Rainer; Diekmann, Bernhard

    2016-05-01

    The carbonate-free abyss of the North Pacific defies most paleoceanographic proxy methods and hence remains a "blank spot" in ocean and climate history. Paleomagnetic and rock magnetic, geochemical, and sedimentological methods were combined to date and analyze seven middle to late Pleistocene northwest Pacific sediment cores from water depths of 5100 to 5700 m. Besides largely coherent tephra layers, the most striking features of these records are nearly magnetite-free zones corresponding to glacial marine isotope stages (MISs) 22, 12, 10, 8, 6, and 2. Magnetite depletion is correlated with organic carbon and quartz content and anticorrelated with biogenic barite and opal content. Within interglacial sections and mid-Pleistocene transition glacial stages MIS 20, 18, 16, and 14, magnetite fractions of detrital, volcanic, and bacterial origin are all well preserved. Such alternating successions of magnetic iron mineral preservation and depletion are known from sapropel-marl cycles, which accumulated under periodically changing bottom water oxygen and redox conditions. In the open central northwest Pacific Ocean, the only conceivable mechanism to cause such abrupt change is a modified glacial bottom water circulation. During all major glaciations since MIS 12, oxygen-depleted Antarctic Bottom Water (AABW)-sourced bottom water seems to have crept into the abyssal northwest Pacific below ~5000 m depth, thereby changing redox conditions in the sediment, trapping and preserving dissolved and particulate organic matter and, in consequence, reducing and dissolving both, biogenic and detrital magnetite. At deglaciation, a downward progressing oxidation front apparently remineralized and released these sedimentary carbon reservoirs without replenishing the magnetite losses.

  6. Morphotectonics of the Central Sagaing fault West of Mandalay: Trace of the 1839 Ava Earthquake Rupture

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Tapponnier, P.; Aung, T.; Tun, S. T.; Khaing, S. N.; Aung, L. T.; Sieh, K.

    2014-12-01

    Using high-resolution optical satellite imagery, and a 3-10 m resolution digital elevation model derived from declassified CORONA imagery, we mapped the trace of the central Sagaing fault and associated geomorphic features along the western flank of the Sagaing Hills. This approximately 350-km-long stretch of the Sagaing fault, which slips at about 2 cm/yr, lies only ~ 10 km west of the densely populated city of Mandalay. Much of this stretch of the fault has not produced a major earthquake (M > 7+) for over one century, and therefore is one of the potentially most dangerous seismic sources in SE Asia. Our new geomorphic mapping reveals more complex deformation patterns along the western side of the Sagaing Hills than hitherto pictured on published maps. The CORONA DEM shows clear evidence of on-going dextral transpression along the fault, consistent with the minor shortening component revealed by GPS (e.g., Socquet et al., 2006). Several hundreds of meters long, right-stepping step-overs characterize the fault north of the well-known Yega-In pull-part basin/lake, forming a series of overlapping dextral scarps at the surface. Our preliminary field and remote sensing observations suggest that the 1839 Ava earthquake, which may be the latest, largest destructive event along this section of the fault, was a great earthquake. We found minimum right-lateral displacements of about 5 to 7 meters. Such large amounts of plausibly single event co-seismic offsets suggest that the Mw magnitude of the 1839 earthquake may have ranged between 7.4 to 8+, which could scale with up to 300+ km rupture length (e.g., Biasi and Weldon, 2006) along the central Sagaing fault seismic gap, between Sagaing and Naypyidaw.

  7. Preliminary paleoseismic observations along the western Denali fault, Alaska

    NASA Astrophysics Data System (ADS)

    Koehler, R. D.; Schwartz, D. P.; Rood, D. H.; Reger, R.; Wolken, G. J.

    2013-12-01

    The Denali fault in south-central Alaska, from Mt. McKinley to the Denali-Totschunda fault branch point, accommodates ~9-12 mm/yr of the right-lateral component of oblique convergence between the Pacific/Yakutat and North American plates. The eastern 226 km of this fault reach was part of the source of the 2002 M7.9 Denali fault earthquake. West of the 2002 rupture there is evidence of two large earthquakes on the Denali fault during the past ~550-700 years but the paleoearthquake chronology prior to this time is largely unknown. To better constrain fault rupture parameters for the western Denali fault and contribute to improved seismic hazard assessment, we performed helicopter and ground reconnaissance along the southern flank of the Alaska Range between the Nenana Glacier and Pyramid Peak, a distance of ~35 km, and conducted a site-specific paleoseismic study. We present a Quaternary geologic strip map along the western Denali fault and our preliminary paleoseismic results, which include a differential-GPS survey of a displaced debris flow fan, cosmogenic 10Be surface exposure ages for boulders on this fan, and an interpretation of a trench across the main trace of the fault at the same site. Between the Nenana Glacier and Pyramid Peak, the Denali fault is characterized by prominent tectonic geomorphic features that include linear side-hill troughs, mole tracks, anastamosing composite scarps, and open left-stepping fissures. Measurements of offset rills and gullies indicate that slip during the most recent earthquake was between ~3 and 5 meters, similar to the average displacement in the 2002 earthquake. At our trench site, ~ 25 km east of the Parks Highway, a steep debris fan is displaced along a series of well-defined left-stepping linear fault traces. Multi-event displacements of debris-flow and snow-avalanche channels incised into the fan range from 8 to 43 m, the latter of which serves as a minimum cumulative fan offset estimate. The trench, excavated into

  8. Stress triggering in en echelon thrust ruptures and related tear faults: The 2003 M=6.9 Zemmouri, Algeria, earthquake and fault interactions

    NASA Astrophysics Data System (ADS)

    Lin, J.; Stein, R. S.; Meghraoui, M.; Toda, S.; Ayadi, A.; Dorbath, C.; Belabbes, S.

    2009-12-01

    The contractional tectonics of northern Algeria is characterized by a series of en echelon thrust faults of moderate lengths (Meghraoui et al., 2000). This tectonic deformation pattern is similar in geometry to other continental thrust fault systems, such as the Coalinga-Kettleman Hills faults in central California, but differs significantly from that of subduction zones, where thrust segments are often more geometrically continuous along the strike of subduction zones. In this study we first illustrate the essential features of stress interaction between earthquakes occurring on en echelon thrust faults and adjacent tear faults. Our model results reveal that earthquakes on en echelon thrust segments could significantly promote strike-slip motion on the intervening tear faults. Furthermore, if the source earthquake has mixed thrust and strike-slip components, the resultant stress increases on the tear faults are even greater. Thus, tear faults may play an important role in stress transfer between adjacent thrust segments. We next examine the stress transferred by the 2003 M=6.9 Zemmouri quake to nearby thrust and strike-slip faults in northern Algeria. Mahsas et al. (2008) illustrated that the observed afterslip in 2003-2005 appears to be concentrated at the upper parts of the 2003 Zemmouri rupture surface. Our calculations support the hypothesis that a significant portion (more than 75%) of the observed afterslip area might have experienced Coulomb stress increases during the Zemmouri main shock. Calculations further reveal that the majority (more than 90%) of the 30 best-relocated aftershocks as determined by Ayadi et al. (2008) also sustained Coulomb stress increases on at least one of their nodal planes. Finally, we calculated that the Zemmouri main shock brought the Coulomb stress 1 bar closer to failure on the adjacent Boumerdes reverse fault and 0.5 bars closer on the right-lateral Thenia faults that bound the Mitidja basin. Both of these faults experienced

  9. Mesozoic and Cenozoic structural geology of the CP Hills, Nevada Test Site, Nye County, Nevada; and regional implications

    SciTech Connect

    Caskey, S.J.

    1991-08-01

    Detailed mapping and structural analysis of upper Proterozoic and Paleozoic rocks in the CP Hills of the Nevada Test Site, together with analysis of published maps and cross sections and a reconnaissance of regional structural relations indicate that the CP thrust of Barnes and Poole (1968) actually comprises two separate, oppositely verging Mesozoic thrust systems: (1) the west-vergent CP thrust which is well exposed in the CP Hills and at Mine Mountain, and (2) the east-vergent Belted Range thrust located northwest of Yucca Flat. West-vergence of the CP thrust is indicated by large scale west-vergent recumbent folds in both its hangingwall and footwall and by the fact that the CP thrust ramps up section through hangingwall strata toward the northwest. Regional structural relations indicate that the CP thrust forms part of a narrow sigmoidal belt of west-vergent folding and thrusting traceable for over 180 km along strike. The Belted Range thrust represents earlier Mesozoic deformation that was probably related to the Last Chance thrust system in southeastern California, as suggested by earlier workers. A pre-Tertiary reconstruction of the Cordilleran fold and thrust belt in the region between the NTS and the Las Vegas Range bears a close resemblance to other regions of the Cordillera and has important implications for the development of hinterland-vergent deformation as well as for the probable magnitude of Tertiary extension north of Las Vegas Valley. Subsequent to Mesozoic deformation, the CP Hills were disrupted by at least two episodes of Tertiary extensional deformation: (1) an earlier episode represented by pre-middle Miocene low-angle normal faults, and (2) a later, post-11 Ma episode of high-angle normal faulting. Both episodes of extension were related to regional deformation, the latter of which has resulted in the present basin and range topography of the NTS region.

  10. Cable fault locator research

    NASA Astrophysics Data System (ADS)

    Cole, C. A.; Honey, S. K.; Petro, J. P.; Phillips, A. C.

    1982-07-01

    Cable fault location and the construction of four field test units are discussed. Swept frequency sounding of mine cables with RF signals was the technique most thoroughly investigated. The swept frequency technique is supplemented with a form of moving target indication to provide a method for locating the position of a technician along a cable and relative to a suspected fault. Separate, more limited investigations involved high voltage time domain reflectometry and acoustical probing of mine cables. Particular areas of research included microprocessor-based control of the swept frequency system, a microprocessor based fast Fourier transform for spectral analysis, and RF synthesizers.

  11. Fault tolerant linear actuator

    DOEpatents

    Tesar, Delbert

    2004-09-14

    In varying embodiments, the fault tolerant linear actuator of the present invention is a new and improved linear actuator with fault tolerance and positional control that may incorporate velocity summing, force summing, or a combination of the two. In one embodiment, the invention offers a velocity summing arrangement with a differential gear between two prime movers driving a cage, which then drives a linear spindle screw transmission. Other embodiments feature two prime movers driving separate linear spindle screw transmissions, one internal and one external, in a totally concentric and compact integrated module.

  12. Computer hardware fault administration

    DOEpatents

    Archer, Charles J.; Megerian, Mark G.; Ratterman, Joseph D.; Smith, Brian E.

    2010-09-14

    Computer hardware fault administration carried out in a parallel computer, where the parallel computer includes a plurality of compute nodes. The compute nodes are coupled for data communications by at least two independent data communications networks, where each data communications network includes data communications links connected to the compute nodes. Typical embodiments carry out hardware fault administration by identifying a location of a defective link in the first data communications network of the parallel computer and routing communications data around the defective link through the second data communications network of the parallel computer.

  13. Ius Chasma Fault

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-415, 8 July 2003

    This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a 'text-book example' of an offset in layered rock caused by a fault. The offset is most easily seen near the upper right of the image. The martian crust is faulted, and the planet has probably experienced 'earthquakes' (or, marsquakes) in the past. This scene is located on the floor of Ius Chasma near 7.8oS, 80.6oW. Sunlight illuminates the scene from the upper left.

  14. DIFFERENTIAL FAULT SENSING CIRCUIT

    DOEpatents

    Roberts, J.H.

    1961-09-01

    A differential fault sensing circuit is designed for detecting arcing in high-voltage vacuum tubes arranged in parallel. A circuit is provided which senses differences in voltages appearing between corresponding elements likely to fault. Sensitivity of the circuit is adjusted to some level above which arcing will cause detectable differences in voltage. For particular corresponding elements, a group of pulse transformers are connected in parallel with diodes connected across the secondaries thereof so that only voltage excursions are transmitted to a thyratron which is biased to the sensitivity level mentioned.

  15. Fault terminations, Seminoe Mountains, Wyoming

    SciTech Connect

    Dominic, J.B.; McConnell, D.A. . Dept. of Geology)

    1992-01-01

    Two basement-involved faults terminate in folds in the Seminoe Mountains. Mesoscopic and macroscopic structures in sedimentary rocks provide clues to the interrelationship of faults and folds in this region, and on the linkage between faulting and folding in general. The Hurt Creek fault trends 320[degree] and has maximum separation of 1.5 km measured at the basement/cover contact. Separation on the fault decreases upsection to zero within the Jurassic Sundance Formation. Unfaulted rock units form an anticline around the fault tip. The complementary syncline is angular with planar limbs and a narrow hinge zone. The syncline axial trace intersects the fault in the footwall at the basement/cover cut-off. Map patterns are interpreted to show thickening of Mesozoic units adjacent to the syncline hinge. In contrast, extensional structures are common in the faulted anticline within the Permian Goose Egg and Triassic Chugwater Formations. A hanging wall splay fault loses separation into the Goose Egg formation which is thinned by 50% at the fault tip. Mesoscopic normal faults are oriented 320--340[degree] and have an average inclination of 75[degree] SW. Megaboudins of Chugwater are present in the footwall of the Hurt Creek fault, immediately adjacent to the fault trace. The Black Canyon fault transported Precambrian-Pennsylvanian rocks over Pennsylvanian Tensleep sandstone. This fault is layer-parallel at the top of the Tensleep and loses separation along strike into an unfaulted syncline in the Goose Egg Formation. Shortening in the pre-Permian units is accommodated by slip on the basement-involved Black Canyon fault. Equivalent shortening in Permian-Cretaceous units occurs on a system of thin-skinned'' thrust faults.

  16. Fault displacement hazard for strike-slip faults

    USGS Publications Warehouse

    Petersen, M.D.; Dawson, T.E.; Chen, R.; Cao, T.; Wills, C.J.; Schwartz, D.P.; Frankel, A.D.

    2011-01-01

    In this paper we present a methodology, data, and regression equations for calculating the fault rupture hazard at sites near steeply dipping, strike-slip faults. We collected and digitized on-fault and off-fault displacement data for 9 global strikeslip earthquakes ranging from moment magnitude M 6.5 to M 7.6 and supplemented these with displacements from 13 global earthquakes compiled byWesnousky (2008), who considers events up to M 7.9. Displacements on the primary fault fall off at the rupture ends and are often measured in meters, while displacements on secondary (offfault) or distributed faults may measure a few centimeters up to more than a meter and decay with distance from the rupture. Probability of earthquake rupture is less than 15% for cells 200 m??200 m and is less than 2% for 25 m??25 m cells at distances greater than 200mfrom the primary-fault rupture. Therefore, the hazard for off-fault ruptures is much lower than the hazard near the fault. Our data indicate that rupture displacements up to 35cm can be triggered on adjacent faults at distances out to 10kmor more from the primary-fault rupture. An example calculation shows that, for an active fault which has repeated large earthquakes every few hundred years, fault rupture hazard analysis should be an important consideration in the design of structures or lifelines that are located near the principal fault, within about 150 m of well-mapped active faults with a simple trace and within 300 m of faults with poorly defined or complex traces.

  17. Fault tree models for fault tolerant hypercube multiprocessors

    NASA Technical Reports Server (NTRS)

    Boyd, Mark A.; Tuazon, Jezus O.

    1991-01-01

    Three candidate fault tolerant hypercube architectures are modeled, their reliability analyses are compared, and the resulting implications of these methods of incorporating fault tolerance into hypercube multiprocessors are discussed. In the course of performing the reliability analyses, the use of HARP and fault trees in modeling sequence dependent system behaviors is demonstrated.

  18. Interbed Modeling to Predict Wellbore Damage for Big Hill Strategic Petroleum Reserve

    NASA Astrophysics Data System (ADS)

    Park, Byoung Yoon

    2014-09-01

    Oil leaks were found in wellbores of Caverns 105 and 109 at the Big Hill Strategic Petroleum Reserve site. According to the field observations, two instances of casing damage occurred at the depth of the interbed between the caprock bottom and salt top. A three-dimensional finite element model, which allows each cavern to be configured individually, was constructed to investigate horizontal and vertical displacements in each well as it crosses the various interbeds. The model contains interfaces between each lithology and a shear zone (fault) to examine the interbed behavior in a realistic manner. This analysis results indicate that the casings of Caverns 105 and 109 failed, respectively, from shear stress that exceeded the casing shear strength due to the horizontal movement of the salt top relative to the caprock and tensile stress due to the downward movement of the salt top from the caprock. The wellbores of Caverns 114 and 104, located at the far end of the field and near the fault, respectively, are predicted to fail by shear stress in the near future. The wellbores of inmost Caverns 107 and 108 are predicted to fail by tensile stress in the near future. The salt top subsides because the volumes of caverns in the salt dome decrease with time due to salt creep closure, while the caprock does not subside at the same rate as the salt top because the caprock is thick and stiff. This discrepancy yields deformation of the well.

  19. 265. Dennis Hill, Photographer April 1998 DETAIL VIEW OF TENSION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    265. Dennis Hill, Photographer April 1998 DETAIL VIEW OF TENSION EYE BARS AT CANTILEVER TRUSS, FACING SOUTHWEST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  20. 266. Dennis Hill, Photographer June 1998 DETAIL VIEW OF TENSION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    266. Dennis Hill, Photographer June 1998 DETAIL VIEW OF TENSION EYE BARS AND COMPRESSION MEMBERS ABOVE UPPER DECK, FACING SOUTHEAST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  1. 35. VIEW OF HOWLAND HILL ROAD, JEDEDIAH SMITH STATE PARK. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    35. VIEW OF HOWLAND HILL ROAD, JEDEDIAH SMITH STATE PARK. CRESCENT CITY, DEL NORTE COUNTY, CALIFORNIA. LOOKING E. - Redwood National & State Parks Roads, California coast from Crescent City to Trinidad, Crescent City, Del Norte County, CA

  2. VIEW OF HOWLAND HILL ROAD, JEDEDIAH SMITH STATE PARK. CRESCENT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF HOWLAND HILL ROAD, JEDEDIAH SMITH STATE PARK. CRESCENT CITY, DEL NORTH COUNTY, CALIFORNIA. LOOKING ESE. - Redwood National & State Parks Roads, California coast from Crescent City to Trinidad, Crescent City, Del Norte County, CA

  3. VIEW OF HOWLAND HILL ROAD, JEDEDIAH SMITH STATE PARK. CRESCENT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF HOWLAND HILL ROAD, JEDEDIAH SMITH STATE PARK. CRESCENT CITY, DEL NORTE COUNTY, CALIFORNIA. LOOKING E. - Redwood National & State Parks Roads, California coast from Crescent City to Trinidad, Crescent City, Del Norte County, CA

  4. VIEW OF HOWLAND HILL ROAD, JEDEDIAH SMITH STATE PARK. CRESCENT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF HOWLAND HILL ROAD, JEDEDIAH SMITH STATE PARK. CRESCENT CITY, DEL NORTE COUNTY, CALIFORNIA. LOOKING W. - Redwood National & State Parks Roads, California coast from Crescent City to Trinidad, Crescent City, Del Norte County, CA

  5. Hill Stability in the Finite Density N-Body Problem

    NASA Astrophysics Data System (ADS)

    Scheeres, Daniel J.

    2016-05-01

    A Celestial Mechanics system is Hill Stable if its components cannot escape from each other. Such stability is difficult to prove for general Celestial Mechanics problems with N ≥ 3 bodies interacting with each other. This is in part due to the ability of two bodies to come arbitrarily close to each other, freeing kinetic energy that can be used for an additional body to escape. When considering bodies with finite density, meaning that they have finite sizes and their mass centers cannot come arbitrarily close to each other, this pathway to escape has specific limits that make the determination of Hill Stability feasible. This opens up new definitions of Hill Stability that can be used to determine energetic thresholds at which a rubble pile body with sufficient angular momentum can shed mass components of various sizes. This talk will review recent advances in Hill Stability with direct application to the interaction of self-gravitating rubble pile bodies.

  6. 1. Historic American Buildings Survey Joseph Hill, Photographer October 1936 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Historic American Buildings Survey Joseph Hill, Photographer October 1936 #12 EARLY RED BRICK HOUSE, Elk and Prospect Sts., Galena, Illinois - Galena Doorways, Red Brick House, Elk & Prospect Streets, Galena, Jo Daviess County, IL

  7. Dennis Hill, Photographer May 1998 DETAIL VIEW OF WINDOW AT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Dennis Hill, Photographer May 1998 DETAIL VIEW OF WINDOW AT TORPEDO ASSEMBLY BUILDING, FACING SOUTHEAST - Torpedo Assembly Building, Eastern end of Yerba Buena Island, San Francisco, San Francisco County, CA

  8. EXTERIOR, A view looking northwest from far hill toward the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    EXTERIOR, A view looking northwest from far hill toward the Mounds complex and the HH Building - Department of Energy, Mound Facility, Hydrolysis House Building (HH Building), One Mound Road, Miamisburg, Montgomery County, OH

  9. 6. Historic American Buildings Survey Joseph Hill, Photographer April 1, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Historic American Buildings Survey Joseph Hill, Photographer April 1, 1936 MANTEL 1352 W. Washington Blvd., Chicago - Chicago Ironwork, William M. Strong Estate (Cast Iron House & Gate), 1352 West Washington Boulevard, Chicago, Cook County, IL

  10. 4. Historic American Buildings Survey Joseph Hill, Photographer April 5, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. Historic American Buildings Survey Joseph Hill, Photographer April 5, 1936 INRON WINDOW GRILL, 1352 W. WASHINGTON ST. CHICAGO - Chicago Ironwork, William M. Strong Estate (Cast Iron House & Gate), 1352 West Washington Boulevard, Chicago, Cook County, IL

  11. 2. Historic American Buildings Survey Joseph Hill, Photographer May 10, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Historic American Buildings Survey Joseph Hill, Photographer May 10, 1936 CAST IRON GATE AT 1352 W. Washington Blvd., Chicago - Chicago Ironwork, William M. Strong Estate (Cast Iron House & Gate), 1352 West Washington Boulevard, Chicago, Cook County, IL

  12. Context view looking west from hill with tree in foreground. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Context view looking west from hill with tree in foreground. Entist Mountains are in distance. - Badger Mountain Lookout, .125 mile northwest of Badger Mountain summit, East Wenatchee, Douglas County, WA

  13. 215. Dennis Hill, Photographer May 1998 DETAIL VIEW OF STRAND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    215. Dennis Hill, Photographer May 1998 DETAIL VIEW OF STRAND SHOES AND STORM CABLE EYE BARS IN YERBA BUENA ANCHORAGE, FACING EAST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  14. 81. VIEW NORTH ON WEST SIDE OF GUN HILL PLATFORM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    81. VIEW NORTH ON WEST SIDE OF GUN HILL PLATFORM SHOWING LAMP STANDARDS FOR NIGHT LIGHTNING. - Interborough Rapid Transit Company, Third Avenue Elevated Line, Borough of the Bronx, New York County, NY

  15. View looking east over coal tipple toward Friendship Hill, home ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View looking east over coal tipple toward Friendship Hill, home of Albert Gallatin, in right background behine bridge. - Monongahela Railroad, New Geneva Bridge, Spanning Monongahela River, South of Lock & Dam No. 7, New Geneva, Fayette County, PA

  16. Symmetric periodic solutions of the Hill's problem. I

    NASA Astrophysics Data System (ADS)

    Batkhin, A. B.

    2013-07-01

    The planar circular Hill's problem is considered, as well as its limiting integrable variant called the Hénon problem, for which the original Hill's problem is a singular perturbation. Among solutions to the Hénon problem there are a countable number of generating solutions-arcs that are uniquely determined by the condition of successive passage through the origin of coordinates—singular point of equations of motion of the Hill's problem. Using the generating solutions-arcs as "letters" of a certain "alphabet", one can compose, according to some rules, the "words": generating solutions of families of periodic orbits of the Hill's problem. The sequence of letters in a word determines the order of orbit transfer from one invariant manifold to another, while the set of all properly specified words determine the system's symbolic dynamics.

  17. VIEW OF SURGE TANK AND TRANSFORMER YARD FROM HILL ABOVE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF SURGE TANK AND TRANSFORMER YARD FROM HILL ABOVE POWERHOUSE. PHOTO BY JET LOWE, HAER, 1995. - Elwha River Hydroelectric System, Glines Hydroelectric Dam & Plant, Port Angeles, Clallam County, WA

  18. TRANSMISSION TOWERS WITH LIGHTENING ARRESTORS ON HILL NORTH OF ELWHA ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    TRANSMISSION TOWERS WITH LIGHTENING ARRESTORS ON HILL NORTH OF ELWHA POWERHOUSE. PHOTO BY JET LOWE, HAER, 1995. - Elwha River Hydroelectric System, Elwha Hydroelectric Dam & Plant, Port Angeles, Clallam County, WA

  19. 28. VIEW OF BRIDGE, LOOKING WEST FROM CREST OF HILL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. VIEW OF BRIDGE, LOOKING WEST FROM CREST OF HILL ABOVE EAST TOWER. NOTE SWAY CABLES ON EACH SIDE OF THE WALKWAY. March 1987 - Verde River Sheep Bridge, Spanning Verde River (Tonto National Forest), Cave Creek, Maricopa County, AZ

  20. 24. VIEW FORM NORTHWEST, WHERE HOUSE RECEDES INTO HILL, SHOWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. VIEW FORM NORTHWEST, WHERE HOUSE RECEDES INTO HILL, SHOWING ROOF, CHIMNEY AND OCTAGONAL SKYLIGHT TO KITCHEN IN CENTER - Isaac N. Hagan House, Kentuck Knob, U.S. Route 40 vicinity (Stewart Township), Chalkhill, Fayette County, PA